Plants- Animals Science News

How Squirrels Learn From Others How To Steal Food

2009-08-06T08:09:00.001-07:00

The ability of gray squirrels to learn from observing others is highlighted in a new study. The research shows how squirrels can quickly learn from watching their peers, particularly if it relates to stealing food. The research adds to growing evidence that animals are primed to learn quickly about what is most important to their survival and that they learn by observing others. It is the first study to test the ability of gray squirrels to learn from observation.

The research team tested the squirrels' ability to learn to choose between two pots of food after watching another squirrel remove a nut from one of the pots. One group was rewarded for choosing the same pot as the previous squirrel, the second group was rewarded for targeting the other pot.

Those that were rewarded for choosing food from the other pot learned more quickly than those that were rewarded for choosing the same pot. This suggests that grey squirrels learn more quickly to recognise the absence of food.

The study was repeated, but instead of observing another squirrel, the animals were trained with the use of a card. In this test, the squirrels showed no significant difference in their ability to learn to choose the same or opposite pot.

The study suggests that squirrels are primed to recognise other squirrels as potential food thieves. It also shows that they learn more quickly from real life observations.

Corresponding author Dr Lisa Leaver of the University of Exeter, said: "Our study is significant because it is the first to show that grey squirrels learn from observing others. It adds to growing evidence that all kinds of animals, from humans and other primates to many species of birds, learn from observation and that they have evolved to learn quickly about those things that are most important to their lives – in the case of grey squirrels, gathering and storing nuts."

The research team now hopes to conduct further studies into the psychology of grey squirrels to learn more about how the animals learn from – and possibly deceive – one another.

http://www.exeter.ac.uk/

Sex Involved In Plant Defense

2009-07-15T00:02:00.001-07:00

Why do some plants defend themselves from insect attacks better than others? New evidence shows that the difference might be due to whether they're getting any plant love.

In research published in Proceedings of the National Academy of Sciences, scientists from North Carolina State University and Duke University discovered that sexually produced evening primrose plants withstand attacks from plant-eaters like caterpillars better than plant relatives that reproduce by themselves.

The findings are important steps to learning more about how plants have evolved defenses against insect herbivores, says Dr. Marc Johnson, assistant professor of plant biology at NC State and the lead author of the research paper.

"The variation in sexual reproduction has a large impact on the ability of plants to evolve defenses against herbivores," Johnson says.

In the study, the researchers performed both lab and field experiments on evening primrose (Onagraceae) plants, a plant family that has 259 different species – 85 percent of which reproduce sexually with the remainder reproducing asexually – to gauge the effects of plant sex on defense mechanisms. The researchers found that so-called generalist herbivores – those that eat a variety of plants – preferred to feed on the asexual species and lived longer while doing so.

The results were a bit different for so-called "specialist" plant-eaters, however. Those insects that prefer just one kind of food were more apt to munch on sexually reproduced species of plant. This most likely occurs, Johnson says, because specialized plant-eaters evolve alongside their hosts and have found ways to co-opt plant defenses. Instead of being deterred by certain chemical compounds produced as defenses by the plant, the specialized plant-eaters are attracted to them.

Johnson says the nuanced results make sense.

"Sex shuffles up genes and allows individual plants to get rid of bad genes and keep good ones," he said. "That helps them evolve defenses against generalist herbivores. Though there are short-term benefits to asexual reproduction – populations can grow more rapidly and propagate even when pollination is not possible – losing sex puts plants at a long-term disadvantage.

The research was funded by NC State, the Natural Sciences and Engineering Research Council of Canada, the National Science Foundation, Duke University and the National Institutes of Health. Johnson's co-authors from Duke University are Dr. Mark D. Rausher, professor of biology, and Dr. Stacey D. Smith, a post-doctoral researcher in biology.

http://www.ncsu.edu/

Cloned Crops Closer To Being Realized

2009-06-09T10:04:00.000-07:00

http://www.plos.org/

No human is a clone of their parents but the same cannot be said for other living things. While your DNA is a combination of half your mother and half your father, other species do things differently. The advantage of clonal reproduction is that it produces an individual exactly like an existing one—which would be very useful for farmers who could replicate the best of their animals or crops without the lottery of sexual reproduction. Clonal reproduction of crop species took a step closer to being realised with new research published in PLoS Biology.
The type of cell division that creates eggs and sperm is called meiosis, and it differs from 'normal' cell division (mitosis) because instead of producing two genetically identical daughter cells, it produces four cells each containing only half of the parental amount of DNA. Meiosis occurs in all species that reproduce sexually, from microorganisms such as yeast to plants, animals and human beings. This new paper blurs the line between the two different types of cell division by showing a plant where three specific mutations are experimentally combined. These divisions are normally meiotic – which make pollen and egg cells – and are replaced by mitotic divisions.

The work, by a team of researchers in France and Austria, is potentially very important commercially, because it makes the creation of stable new mutant crops—such as plants of a different colour, or with a different yield, etc.—much simpler. It is now much closer to being possible to reproduce a plant that produces perfect potatoes, maize or rice, without the lottery of reassortment that each meiotic division and ensuing fertilization introduces.

The first steps of both meiosis and mitosis are the replication of the dividing cell's DNA. Once replication has occurred, the chromosomes condense into tightly bound structures, and in mitosis these form an X shape in which each half of the X is a chromatid, comprising one complete copy of the chromosome. The double-chromatid chromosomes line up along the centre of the cell. In mitosis, the two chromatids are pulled apart—the X is divided along one axis of symmetry—and these then pass into two genetically identical daughter cells. In meiosis, there are two lining up and dividing phases. The first lining up is of homologous chromosomes—all chromosomes in an adult cell have a partner, members of the partnership coming from the mother and father of the cell—and these homologous chromosomes are each made up of two chromatids. The first division divides homologous pairs of chromosomes while the second meiotic division is just like the mitotic di vision: the chromosomes line up at the middle of the new cell and the chromatids divide at the centre of the X.

Thus the differences between mitosis and meiosis are that meiosis has two rounds of division; co-segregation of sister chromatids at the first division; and recombination that occurs during the first division—a swapping over process that adds more genetic diversity to offspring. The new work, led by Raphael Mercier, identifies a gene that controls one of these three features—entry into the second meiotic division—in the sexual plant Arabidopsis thaliana. By combining a mutation in this gene with two other previously described mutations—one that eliminates recombination and another that modifies chromosome segregation—the authors have created a strain of plant (called MiMe for 'mitosis instead of meiosis') in which meiosis is totally replaced by mitosis.

MiMe plants produce pollen and eggs that are genetically identical to their parent. If MiMe eggs are self-fertilized by MiMe sperm, the offspring plant has twice as much DNA as the parent generation, and has all the genes from this single parent.

Thus the authors have made a form of asexual reproduction possible in a normally sexual species. Turning meiosis into mitosis is not enough to reach clonal reproduction, but it's a giant leap towards it. This has potential revolutionary applications in crop improvement and propagation.

This work was supported by an INRA postdoctoral fellowship to Id'E. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Cuckoo Joins List Of Threatened Birds

2009-06-09T10:02:00.000-07:00

http://www.rspb.org.uk/ The latest assessment of the status of all of the UK’s 246 regularly occurring birds – Birds of Conservation Concern 3 – shows 52 are now of the highest conservation concern and have been placed on the 'red list'.

The revised red list now includes even more familiar countryside birds, including the cuckoo, lapwing and yellow wagtail, joining other widespread species such as the turtle dove, grey partridge, house sparrow and starling.

Alarmingly, red listed species now account for more than one-in-five (21 per cent) of all the UK’s bird species. This is a far higher proportion than compared to the last assessment in 2002, when 40 species (16 per cent) were red listed. Most species on the red list have suffered a recent halving of range or population in the UK, or have undergone a historical decline since 1800.

Amongst the species new to the red list is a suite of birds visiting the UK in summer, notably the cuckoo, wood warbler, and tree pipit. These birds, are widespread, but rapidly-declining, summer visitors to the UK.

Their addition to the red list is highlighting the concern that many long-distance migratory birds nesting in Europe and wintering in Africa are increasingly in trouble. Currently 21 of the birds on the red list are summer visitors to the UK, with the majority of these spending the winter in sub-Saharan Africa.

The continued decline of widespread farmland and woodland birds is a theme which has developed since the compilation of the last list in 2002. Lapwing, a formerly much-more widespread wading bird, and the hawfinch, a woodland bird largely confined to England, have both joined the red list in the latest assessment.

Three species of seabird join the red list for the first time. The Balearic shearwater - a smaller relative of the albatross - visits the UK from its Mediterranean breeding grounds regularly each autumn. This seabird, which is thought to face a higher risk of global extinction even than the giant panda - is the rarest bird to regularly occur in the UK.

Highlighting concerns about the fortunes of seabirds around the northern coasts of the British Isles, the Arctic skua has joined the red list straight from the 2002 green list: the only species to do so. The familiar herring gull also joins the red list as its population has more than halved in recent times.

For the first time two winter-visiting birds have joined the red list. The dunlin, a starling-sized wading bird, and the scaup - a duck - have been placed on the red list because of declines in wintering populations. The ongoing decline of the dunlin population has seen this wader slump to its lowest levels since recording began.

While a link to climate change has not been demonstrated, the addition of five species on the southern edge of their nesting range in Britain (Temminck’s stint, ruff, whimbrel, redwing and fieldfare) to the red list may provide some the evidence of range shifts. These species have only had a toehold in the UK in recent decades and now that appears to be slipping. (However, redwing and fieldfare are still plentiful visitors to the UK in winter).

Good news

However, the 2009 assessment does contain some good news. Six species (stone-curlew, woodlark, quail, Scottish crossbill, bullfinch and reed bunting) have been removed from the 2002 red list, largely because of a recovery in their numbers or range, or a better understanding of their populations. These species are now placed on the amber list.

The stone-curlew is a bird of farmland and open countryside. Virtually confined to Wessex and central East Anglia, the stone-curlew population has increased because of the fantastic efforts by landowners to improve the fortunes of this striking wading bird.

'Conservation works, but with a growing to-do list we have to strive even harder to retain the rich variety of wildlife that our islands possess.'

Improvements in land management, especially of heathland, have also led to a dramatic increase in the UK population of the woodlark, a heathland bird. The bullfinch and the reed bunting have also been placed on the amber list following modest recoveries in their populations.

Scottish crossbill stable

The Scottish crossbill – the only bird species with its total world range confined to the UK – has also been removed from the red list. A survey (funded by RSPB and Scottish Natural Heritage) found approximately 13,000 individuals of this colourful endemic finch, and its population is currently thought to be stable.

Five species assessed in 2002 (bluethroat, scarlet rosefinch, icterine warbler, hoopoe and snow goose) were not considered in the 2009 revision, because they failed to meet the qualifying criteria for inclusion.

Four species not assessed in 2002 (Balearic shearwater; shorelark; yellow-legged gull; and hooded crow) were considered in the 2009 revision for the first time.

Birds of Conservation Concern 3 is compiled by a partnership of organisations, including the British Trust for Ornithology, Countryside Council for Wales, Game & Wildlife Conservation Trust, Joint Nature Conservation Committee, Natural England, Northern Ireland Environment Agency, RSPB, Scottish Natural Heritage, and the Wildfowl & Wetlands Trust,

The full Birds of Conservation Concern 3 report will be published in the June edition of British Birds.

Wader Populations Decline Faster Than Ever

2009-06-09T09:59:00.000-07:00

According to a new publication by Wetlands International, more than half the populations of waders in Europe, West Asia and Africa are declining at an accelerating rate.

Waders are a group of relatively small waterbirds including species like lapwings, plovers, godwits, curlews and sandpipers. Many of them undertake long distance migrations from their Arctic breeding grounds to wintering areas as far away as Southern Africa. Some concentrate in huge numbers at just a few sites, making these wetlands critical for their survival.

The new ‘Wader Atlas’ is the first comprehensive overview of key site networks for waders in Europe, West Asia and Africa, and the publication highlights a need for better protection of the key wetlands along their flyways, especially in Africa and the Middle East.

The authors outline that whilst many European Union (EU) Member States have established a fairly comprehensive network of protected areas for waders, many of which are Important Bird Areas (IBAs) identified by the BirdLife Partnership, the protection and management of key sites is still far from adequate beyond the EU’s borders.

“Waders such as Ruff [Philomachus pugnax] are heavily protected in the EU; farmers receive thousands of Euros for nest protection”, said author Simon Delany. However, the new publication outlines that resources outside the EU urgently need to be increased – helping to conserving waterbirds at all stages of their lives.

The wetlands of the African west coast are under enormous pressures. The sparse water resources in the Sahelian zone are tapped by dams which have turned formerly shallow wetlands into permanently dry lands. Irrigation schemes for growing human population disrupt the water flow in wetlands such as the shrinking Lake Chad. The atlas also outlines that wetlands themselves are often converted to agricultural use - such as in the Tana River Delta in Kenya, which is threatened by conversion to sugar cane plantations.

“Migratory waterbirds can only be effectively conserved through international cooperation along their entire flyway”, said Dr Vicky Jones - BirdLife’s Global Flyways Officer. “BirdLife Partners are focusing on joining up site-based action at critical sites for waterbirds within the African-Eurasian area”.

BirdLife is a key partner in the Wings over Wetlands (WOW) project which is making an enormous difference to the understanding of migratory waterbirds and their needs, demonstrating best practice in the conservation and wise-use of wetlands, and increasing cooperation along the African-Eurasian flyway.

BirdLife is also involved in a new ‘WetCap’ project to help strengthen waterbird conservation and build capacity for wetland management activities at key sites in Morocco, Tunisia, Algeria, Egypt and Mauritania. “WetCap will promote the wise-use of wetlands which benefit local people by providing clean water and opportunities for fishing, agriculture, recreation and tourism”, said Dr Jones.

On the ground, IBA Caretakers and Site Support Groups are working to protect and monitor key sites for migratory birds. “A wide range of activities are being implemented by the BirdLife Partnership to support the development and growth of this local approach to site conservation, through capacity building, networking, sharing experience and provision of seed-financing”, added Dr Jones.

BirdLife recognises that despite their importance, wetlands are amongst the world’s most vulnerable ecosystems.

Pushing Species To The Brink

2009-06-04T22:46:00.000-07:00

Thirty-five percent of the world’s birds, 52 percent of amphibians and 71 percent of warm-water reef-building corals are likely to be particularly susceptible to climate change, the first results of an IUCN study have revealed.

The report identified more than 90 biological traits which are believed to make species most susceptible to climate change. It found that 3,438 of the world’s 9,856 bird species have at least one out of 11 traits that could make them susceptible to climate change.

Albatross, penguin, petrel and shearwater families are all likely to be susceptible to climate change, while heron and egret families, and osprey, kite, hawk and eagle families are among those least likely to be susceptible to climate change.

“This is the first time that a systematic assessments of species’ susceptibility to climate change has been attempted,” says Wendy Foden, of IUCN’s Species Programme. “Climate change is already happening, but conservation decision makers currently have very little guidance on which species are going to be the worst affected.”

The study found 3,217 of the 6,222 amphibians in the world are likely to be susceptible to climate change. Three salamander families are could be particularly susceptible, while 80-100 percent of Seychelles frogs and Indian Burrowing Frogs, Australian ground frogs, horned toads and glassfrog families were assessed as susceptible.

Specialized habitat requirements, such as species with water-dependant larvae, and those unable to disperse due to barriers such as large water bodies or human-transformed habitats are most at risk.

The report found that 566 of 799 warm-water reef-building coral species are likely to be susceptible to the impacts of climate change. The Acroporidae family, including staghorn corals, had particularly high numbers of susceptible species, while the Fungiidae family, including mushroom corals, and the Mussidae family, including some brain corals, possess relatively few.

Coral species qualified due to their sensitivity to increases in temperature, sedimentation and physical damage from storms and cyclones. Poor dispersal ability and colonization potential were used as a further important indicators.

According to the IUCN Red List of Threatened Species, 32 percent of amphibians are threatened with extinction. Of these, 75 percent are susceptible to climate change while 41 percent of non-threatened species are susceptible to climate change. For birds, the overall percentage of those threatened with extinction is lower – 12 percent. However, 80 percent of those are susceptible to climate change.

“There is a large overlap between threatened and climate change susceptible amphibian and bird species,” says Jean-Christophe Vié, Deputy Head of IUCN Species Programme. “Climate change may cause a sharp rise in the risk and rate of extinction of currently threatened species. But we also want to highlight species which are currently not threatened but are likely to become so as climate change impacts intensify. By doing this we hope to promote preemptive and more effective conservation action.”

http://www.iucn.org/

Common Garden Plant Threatened By Climate Change

2009-06-04T22:45:00.000-07:00

Cyclamen, a common, pretty garden flower, is at risk of extinction because of climate change.

In a study published in the open access journal BMC Evolutionary Biology, researchers show, using mathematical modelling, that the ideal climate for Cyclamen will become increasingly rare and might have totally disappeared by the 2050's. Some species of Cyclamen are adaptable enough and could survive climate change, but many would probably disappear.

Chris Yesson and Alastair Culham, from the University of Reading in the UK built mathematical models based on the current distribution of the 21 different species of Cyclamen, in order to predict the impact of climate change on Cyclamen within the next 50 years.

Yesson and Culham identified distinct climatic niches -- geographic areas with the ideal climate -- for different species of Cyclamen. Most Cyclamen species thrive in a typical Mediterranean climate, with hot, dry summers and cool, wet winters, but many are found in areas with much harsher climatic conditions. Yesson and Culham show that climatic niches are likely to decrease for all species of Cyclamen, and by more than 60% for most species.

Yesson and Culham conclude: "Many of these species are considered to be at high risk of extinction due to climate change."

http://www.biomedcentral.com/

Nature Parks Can Save Species As Climate Changes

2009-06-04T22:43:00.001-07:00

Retaining a network of wildlife conservation areas is vital in helping to save up to 90 per cent of bird species in Africa affected by climate change, according to scientists.

The research team – led by Durham University, including BirdLife International and the RSPB (BirdLife in the UK) – looked at the effects of climate change on 815 bird species of conservation concern in sub-Saharan Africa and on the network of sites designated for them (termed Important Bird Areas).

Published in the journal Ecology Letters, the research – funded by the RSPB – demonstrates that a network of wildlife areas will be a crucial tool to help biodiversity survive future climate change. The findings suggest an urgent need for legislators to protect eco-systems and key wildlife areas in Africa. They show that, over the next 75 years, the biodiversity of some regions will suffer more than others as a result of climate change. They also underline the importance of providing 'green corridors' to help wildlife to move to find new climatically-suitable areas.

The team led by Dr Stephen Willis and Dr David Hole from the School of Biological and Biomedical Sciences at Durham University, used simulation models to see how climate change might affect birds in Important Bird Areas, in the coming decades under a scenario of moderate climate change.

The researchers looked at a network of 863 IBA sites across 42 countries and territories covering around 2,079,306 square kms (1,292,020 square miles) or 7 per cent of the African continent. The sites are identified as being critical for the conservation of birds, in particular, species that are globally threatened, restricted in range or restricted to particular biomes. Together, African IBAs are home to 875 of these species.

Climate change is not the only issue affecting wildlife in Africa. More than 40 per cent of African IBAs lack any form of legal protection under national or international law. Agricultural development, logging, invasive alien species, and unsustainable hunting and trapping are the main threats to bird species and IBAs across the African continent.

Dr Stephen Willis said: "We looked at bird species across the whole network of protected areas in Africa and the results show that wildlife conservation areas will be essential for the future survival of many species of birds.

"Important Bird Areas will provide new habitats for birds that are forced to move as temperatures and rainfall change and food sources become scarce in the areas where they currently occur. Protected areas are a vital conservation tool to help birds adapt to climate change in the 21st century."

The findings show that the biodiversity of particular areas is likely to change significantly. The turnover of species in some sites could be as high as 50 per cent, as established species leave to find more suitable climes or new food supplies, and new species move in to an area. The adaptability of birds will be an important factor, the experts say.

Dr Stephen Willis said: "The results show that 90 per cent of priority species in Africa will find suitable climate somewhere in the network of protected areas in future. However, one in ten birds will have to find new places to live and breed so new sites will have to be added to the IBA network.

"The central regions of Africa should maintain many of their current species as long as the protected areas remain intact. By contrast, areas of the Afrotropical Highlands, which occur in countries such as Cameroon, South Africa and Ethiopia, will see enormous change with more than 40 per cent of species leaving."

The findings also show that some species are likely to struggle, and may even become extinct unless new populations can be established. A priority species might be lost from a particular IBA, but there may be other climatically suitable sites in the network for the species to move to. Many species will only survive if they adapt by moving across Africa to seek out new, climatically-suitable areas to inhabit.

Dr Stuart Butchart, Global Research Coordinator at BirdLife International, said: "The survival of much of the planet's biodiversity under climate change will depend upon adequate protection for biodiverse ecosystems, the IBAs within them, and support for the people who depend on them - so that local communities can participate actively in making their environment more resilient. It is essential that policy leads to adequate protection of IBAs and takes account of the critical role that ecosystems play in helping wildlife and people adapt."

Ruth Davis, head of climate change at the RSPB, said: "Looking after IBAs is vital for the future of our wildlife. Protecting the natural resources and services provided by these ecosystems is vital for people too. Healthy ecosystems are the first line of defence against the impacts of climate change for many of the world's poorest people."

One example, is the Gola Forest Transboundary Peace Park, on the borders of Sierra Leone and Liberia, uniting existing protected IBAs and encompassing additional forest to provide corridors for the movement of wildlife between them. It protects one of the largest remaining blocks of intact forest in the Upper Guinea Area of West Africa.

200 New Species Of Amphibians In Madagascar

2009-06-04T22:42:00.000-07:00

Between 129 and 221 new species of frogs have been identified in Madagascar, practically doubling the currently known amphibian fauna. The finding suggests that the number of amphibian species in Madagascar, one of the world’s biodiversity hotspots, has been significantly underestimated. According to the researchers, if these results are extrapolated at a global scale, the number of amphibian species worldwide could double.
Their study, conducted with participation of the Spanish Scientific Research Council (CSIC), is published in the journal Proceedings of the National Academy of Science.

As Professor David R. Vieites, CSIC researcher at the Spanish National Natural Sciences Museum in Madrid, states: “the diversity of species in Madagascar is far from being known and there is still a lot of scientific research to be done. Our data suggest that the number of new species of amphibians not only has been underestimated but it is spatially widespread, even in well studied areas. For example, two of the most visited and studied National parks, Ranomafana and Mantadía/Analamazaotra, harbour 31 and 10 new species respectively.”

Dr. Frank Glaw, curator of herpetology at the Zoologische Staatssammlung from Munich explains: ”During the past 15 years, we discovered and described over 100 new frog species from Madagascar, which led us to believe that our species inventory is almost complete. But as our new surveys show, there are many more species than we suspected.”

The paper suggests that the total biodiversity on the island could be much higher also in other groups, so the actual destruction of natural habitats may be affecting more species than previously thought. This is important for conservation planning, as the rate of destruction of rainforests in Madagascar has been one of the highest in the planet, with more than 80% of the historic surface of rainforest already lost.

“Although a lot of reserves and national parks have been created in Madagascar during the last decade, the actual situation of politic instability is allowing the cut of the forest within national parks, generating a lot of uncertainty about the future of the planned network of protected areas,” explains Vieites. Almost a quarter of the new species discovered have not been found yet in protected areas.

Biodiversity

The study proposes different criteria -- morphological, genetic and bioacoustic -- to assign the candidate species (the ones which have been identified as potential new species but not yet formerly described) to different categories. In Madagascar, the number of candidate species is higher than the number of described species in some genera.

“Using these criteria and the integration of different techniques under the principle of congruence could help to boost the inventory and the process of species description worldwide,” explains Vieites. Dr. Miguel Vences, professor at the Technical University of Braunschweig adds: "People think that we know which plant and animal species live on this planet. But the century of discoveries has only just begun – the majority of life forms on Earth is still awaiting scientific recognition."

Also participating in the study were researchers from the Technical University of Braunschweig, Museo regionale di Scienze Naturali from Torino, and the Hessisches Landesmuseum from Darmstadt.

Madagascar is the fourth largest island in the world and one of the most biodiverse areas globally, with a high degree of endemic species. “To get an idea of its biodiversity, while in the Iberian Peninsula are about 30 species of amphibians and in Germany about 20, in a single locality in Madagascar we can find ca. 100 species of frogs,” explains Vieites.

http://www.csic.es/index.do

Lizards 'Shout' Against A Noisy Background

2009-06-04T22:39:00.001-07:00

Male anole lizards signal ownership of their territory by sitting up on a tree trunk, bobbing their heads up and down and extending a colorful throat pouch. They can spot a rival lizard up to 25 meters away, said Terry Ord, a postdoctoral researcher at UC Davis who is working with Judy Stamps, professor of evolution and ecology.

The lizards' signals need to be strong enough for a rival to see, but not vivid enough to say "eat me" to a passing predator. But their forest home can be a visually noisy environment, with branches and leaves waving in the breeze and casting patterns of light and shade.

"They have to have a strategy to get their message across," Ord said.

Ord videotaped two species of anole lizards, Anolis cristatellus and Anolis gundlachi, in the Caribbean National Forest in Puerto Rico. He found that the more "visual noise" in the background, the faster and more exaggerated the movements of the lizards.

Anole lizards are interesting to evolutionary biologists because different species are found on different islands all over the Caribbean. The lizards are not particularly closely related -- they are separated by 30 million years of evolution -- but they live in similar environments with the same obstacles to communication. So Ord is using them as a model to investigate the evolution of such signals.

The other authors on the paper, which is published online in Proceedings of the Royal Society part B, are Richard A. Peters, Australian National University, Canberra; and Barbara Clucas, a graduate student in animal behavior at UC Davis. The work was supported by grants from the National Geographic Society, the National Science Foundation and the Australian Research Council.

http://www.ucdavis.edu/index.html

In Lizards, Egg Size Matters

2009-06-04T22:38:00.001-07:00

Whether baby lizards will turn out to be male or female is a more complicated question than scientists would have ever guessed, according to a new report published online on June 4th in Current Biology. The study shows that for at least one lizard species, egg size matters.

"We were astonished," said Richard Shine of the University of Sydney. "Our studies on small alpine lizards have revealed another influence on lizard sex: the size of the egg. Big eggs tend to give girls, and small eggs tend to give boys. And if you remove some of the yolk just after the egg is laid, it's likely to switch to being a boy, even if it has female sex chromosomes; and if you inject a bit of extra yolk, the egg will produce a girl, even if it has male sex chromosomes."

In many animals, the sex of offspring depends on specialized sex chromosomes. In mammals and many reptiles, for instance, males carry one X and one Y chromosome, while females have a pair of X chromosomes. In contrast, animals such as alligators depend on environmental cues like temperature to set the sex of future generations.

The new findings add to evidence that when it comes to genetic versus environmental factors influencing sex determination, it doesn't have to be an either/or proposition. In fact, Shine and his colleagues earlier found in hatchlings of the alpine-dwelling Bassiana duperreyi that extreme nest temperatures can override the genetically determined sex, in some cases producing XX boys and XY girls. His group had also noticed something else: large lizard eggs were more likely to produce daughters and small eggs to produce sons.

Despite the correlation, Shine said he had assumed that the association was indirect. In fact, his colleague Rajkumar Radder conducted studies in which he removed some yolk from larger eggs, more likely to produce daughters, to confirm that assumption.

"We were confident that there would be no effect on hatchling sex whatsoever," Shine said. "When those baby boy lizards started hatching out, we were gob-smacked."

Shine thinks there will be much more to discover when it comes to lizard sex determination.

"I suspect that the ecology of a species will determine how it makes boys versus girls, and that our yolk-allocation effect is just the tip of a very large iceberg," he said.

Predatory Insects May Help Solve Mealybug Problem

2009-06-01T22:44:00.000-07:00

Agricultural Research Service (ARS) scientists and cooperators have joined forces to control the pink hibiscus mealybug, which, if unchecked, could cause an estimated $750 million in crop losses annually in the United States.

This invasive pest, Maconellicoccus hirsutus, was first found in Florida several years ago and is spreading within Florida and to other states. As it feeds, the mealybug injects saliva into the plant, causing malformation, stunting and eventual death.

Research leader David Hall and entomologist Stephen Lapointe of the ARS Subtropical Insects Research Unit (SIRU), Fort Pierce, Fla., are leading an effort to find biological methods to stop the pest.

Before the pest came to Florida in 2002, Lapointe, working in St. Croix, U.S. Virgin Islands, discovered that female pink hibiscus mealybugs (PMH) emit a powerful pheromone that attracts males. To recreate this chemical in the laboratory, Lapointe used a hormone analog to eliminate male PHMs from a colony, leaving only females for pheromone analyses.

He also developed a simple diet for feeding the mealybugs, showing that PHM could be reared--for research purposes--on an artificial diet. Due to the expanding infestation of the mealybug, research to develop an optimal artificial diet was recently initiated at the Fort Pierce laboratory.

In addition to these efforts, the USDA's Animal and Plant Health Inspection Service (APHIS) and the Florida Department of Agriculture and Consumer Services responded to the Florida infestation by releasing two effective mealybug parasites, Anagyrus kamali and Gyranusoidea indica, along with a predatory ladybug, Cryptolaemus montrouzieri. These releases have resulted in a reduction of more than 98 percent in PHM population density in some locations.

Lapointe's new artificial PHM diet will enable the production of larger numbers of healthy mealybugs to rear wasps and ladybugs needed for successful PHM-control programs.

http://www.ars.usda.gov/main/main.htm

Researchers Discover Sex Potion To Ensnare Mealybug Pests

2009-06-01T22:42:00.000-07:00

Agricultural Research Service (ARS) scientists have found a way to entice male pink hibiscus mealybugs (PHMs) to congregate. That leaves the pesky insects--which attack more than 200 species of ornamental, vegetable and citrus crops--open to detection.

A team of researchers led by chemist Aijun Zhang at the ARS Chemicals Affecting Insect Behavior Laboratory (CAIBL), Beltsville, Md., discovered the two compounds that together make up the female PHM's sex pheromone.

The compounds provide a timely method with which to monitor and ultimately reduce infestations. PHMs escape conventional insecticides partly because their outer coatings, or cuticles, are resistant to topical penetration.

Officials with the U.S. Department of Agriculture's Animal and Plant Health Inspection Service (APHIS), Riverdale, Md., are using the PHM-pheromone blend as a sex lure to track mealybug pest infestations in Florida and California. APHIS is also using the pheromone blend to chart the effectiveness of "biological controls," or natural enemies used to combat agricultural pest species.

The ARS scientists are now working with cooperators to improve both the process for producing the PHM pheromone and the method for using the compounds to control infestations. Such methods include technologies to disrupt the PHMs' mating activities, as well as to attract them on a mass scale for removal.

The discovery was published in the Proceedings of the National Academy of Sciences.

Searching For Rare Ladybugs

2009-06-01T22:41:00.001-07:00

Agricultural Research Service (ARS) scientists and cooperators are seeking the public's help in surveying for once-common ladybug species that are now hard to find.

Researchers with ARS, Cornell University at Ithaca, N.Y., and South Dakota State University (SDSU) in Brookings want people to photograph every ladybug possible, and to send the photos to Cornell so researchers can inventory the insects. In particular, the scientists are looking for rare species, such as the nine-spotted, two-spotted and transverse lady beetles.

These beetles were common 20 years ago, but have become harder to find in the past few decades. There are more than 400 ladybug species native to North America, but some have become extremely rare, displaced perhaps by development, pesticides, non-native species and other factors.

Entomologist Louis Hesler at the ARS North Central Agricultural Research Laboratory in Brookings is particularly interested in the nine-spotted, two-spotted and transverse ladybugs because the farm community in South Dakota where he works has depended on these predatory beetles for years to eat insect pests that eat farm crops.

Urban gardeners are interested in ladybugs because they protect garden crops as well. Ladybugs also protect North American forests.

In a survey this past summer, Hesler and colleague Mike Catangui, an entomologist at SDSU in Brookings, found 1,000 ladybugs, but only about 10 each of the three rare species. Hesler and Catangui are co-principal investigators in the SDSU part of the "Lost Ladybug Project."

The project has two facets: the research component, which Hesler, Catangui, and other scientists in New York State are participating in, and the citizen science component.

As part of the citizen science part of the project, researchers are encouraging participation from students who are interested in entomology, agriculture or science.

Those wishing to participate can visit http://www.lostladybug.org for tips on finding and photographing ladybugs and submitting photos. The website includes ways to track and map the Lost Ladybug data.

Botanists Identify New Species Of North American Bamboo

2009-06-01T22:40:00.001-07:00

Two Iowa State University botanists and their colleague at the University of North Carolina have discovered a new species of North American bamboo in the hills of Appalachia. It is the third known native species of the hardy grass. The other two were discovered more than 200 years ago.

ISU botanists Lynn Clark and Jimmy Triplett study bamboo diversity and evolution. They first heard about "hill cane" from University of North Carolina botanist Alan Weakley. As soon as they saw it, they knew it was different.

'Hill cane'

Lynn Clark, Iowa State professor of ecology, evolution and organismal biology, and Ph.D. student Jimmy Triplett study bamboo diversity and evolution. They first heard about "hill cane" from Alan Weakley, a botanist at the University of North Carolina. Although the plant was known to the people in the area, its distinctiveness was not recognized.

Hill cane differs from the other two native North American bamboo species -- commonly known as switch cane and river cane -- in an important way: It drops its leaves in the fall.

"That's why it was recognized locally as being different," Clark said. "It's pretty uncommon for bamboos to drop their leaves."

Clark should know. She's an internationally recognized bamboo expert. She had previously discovered 74 new species of bamboo.

"All the other new ones came from Central and South America," she said. "It's so exciting to find a new species in our own backyard!"

Her 75th species discovery has been named Arundinaria appalachiana. Clark, Triplett and Weakley recently completed the intricate process botanists are obliged to follow to officially name and describe a newfound species. Following rules laid out in the International Code of Botanical Nomenclature, they prepared a short description of the plant in Latin and a longer one in English, and provided drawings and other information to make a strong case for the recognition of A. appalachiana as a distinct species of bamboo. They submitted their evidence in a manuscript to the scientific journal Sida, Contributions to Botany, convincing the peer reviewers that the bamboo they discovered was new. Their study was published last fall.

Bamboos of North America

There are 1,400 known species of bamboo. Of those, about 900 are tropical and 500 are temperate. The bamboos of North America are found in the Eastern and Southeastern United States, from New Jersey south to Florida and west to Texas. River cane (Arundinaria gigantea) occurs in low woods and along riverbanks. Switch cane (Arundinaria tecta) is found in non-alluvial swamps, moist pine barrens, live oak woods and along sandy margins of streams.

"Most people have no idea that we have native bamboo in the U.S.," Clark said. "But it has been a very important plant ecologically. And there's recent interest in using it for re-vegetation projects because it's native and was used for habitat by so many different animals, especially birds."

Building a bamboo family tree

Clark and Triplett began looking at the North American bamboos as part of a larger collaboration with botanists worldwide to develop an evolutionary family tree of bamboo species. They're using modern DNA sequencing technologies together with traditional plant taxonomy, which involves observation and description of a plant's form, anatomy, ecology and other characteristics.

"We want to get the big picture of how all the temperate bamboos are related to each other. That means taking inventory of what exists, then comparing notes," Clark said.

They already know that the closest relatives of native North American bamboos are not in Central or South America, but are in East Asia.

"That's a well-known pattern of diversity in plants and animals. Plants known to be closely related that were previously found across a large area of the earth are only in those two areas now. For various reasons, the Eastern U.S. and East Asia are a repository for a lot of diversity," Clark said.

"But we still don't understand exactly how long it has been since our bamboos separated from their Asiatic cousins. And we don't know how we ended up with three species in North America and 500 in East Asia," she said.

Although botanists had previously studied the North American bamboos, no one had done extensive fieldwork to study and collect the plants in the wild, and questions remained as to whether there was really more than just a single species. In 2003, with funding from the National Geographic Society, Clark and Triplett set off for the Southeast to find the switch cane and river cane in their native habitats.

They knew it was different

"Once we actually saw the plants in the field, we knew quickly that there were two distinct species," Clark said. "But we kept hearing about a third plant, called hill cane."

And as soon as they saw it, they knew it was different.

Remains Of Earliest Giant Panda Discovered

2009-06-01T22:38:00.001-07:00

Although it may sound like an oxymoron, a University of Iowa anthropologist and his colleagues report the first discovery of a skull from a "pygmy-sized" giant panda -- the earliest-known ancestor of the giant panda -- that lived in south China some two million years ago.

The ancestor of today's giant panda really was a pygmy giant panda, says Russell Ciochon, UI professor of anthropology. Ciochon is a co-author of an article published in the June 18-22 online edition of the journal Proceedings of the National Academy of Sciences (PNAS). Previous discoveries of teeth and other remains made between 1985 and 2002 had failed to establish the animal's size.

Ciochon says that the ancient panda (formally known as Ailuropoda microta, or "pygmy giant panda") was probably about three feet in length, compared to the modern giant panda, which averages in excess of five feet in length. Also, like it's modern counterpart, it lived on bamboo shoots, as indicated by wear patterns recorded on teeth and specialized muscle markings, indicating heavy chewing, on the skull.

The new find, made about 18 months ago in a south China karst (limestone) cave by Chinese researchers and co-authors Changzhu Jin and Jinyi Liu of the Chinese Academy of Sciences, shows that the basic anatomy of the giant panda has remained largely unchanged for millions of years.

Ciochon says that the skull --, about one-half the size of a modern-day giant panda skull, but anatomically very similar -- indicates that the giant panda has evolved for more than three million years as a separate lineage apart from other bears and was adapted to eating bamboo very early in its development.

"Pandas are very unique bears --- the only bear species that is known to exist wholly on a vegetarian diet," says Ciochon. "The evolution of this unique dietary specialization probably took millions of years to refine. Our new discovery shows the great time depth of this unique bamboo-eating specialization in pandas. Thus, pandas have been 'uniquely pandas' for many millions of years says Ciochon."

Ciochon says that the find further helps establish conditions that existed in the region during the varying climatic conditions of the Pliocene and Pleistocene epochs, stretching back some three millions years before the present. The pygmy giant panda lived in lowland tropical bamboo forests. It is often found associated with the extinct elephant-like creature, Stegodon, and the giant extinct ape, Gigantopithecus. Today's giant panda is isolated in mountainous upland bamboo forests, partly due to the pressure of modern civilization.

Ciochon, anthropology professor and department chair in the University of Iowa College of Liberal Arts and Sciences, says that he plans to return to China this November to explore new cave sites in collaboration with Chinese colleagues. A Fellow of the American Association for the Advancement of Science, Ciochon is internationally recognized for his contributions to the fields of primate paleontology and paleoanthropology in Asia concerning "anthropoid origins" and Homo erectus evolution and dispersal.

This research was funded by travel grants from UI International Programs, the Dean of the College of Liberal Arts and Sciences, and the Human Evolution Research Fund of the UI Foundation.

Giant Pandas See In Color

2009-06-01T22:37:00.000-07:00

They may be black and white, but new research at the Georgia Institute of Technology and Zoo Atlanta shows that giant pandas can see in color. Graduate researcher Angela Kelling tested the ability of two Zoo Atlanta pandas, Yang Yang and Lun Lun, to see color and found that both pandas were able to discriminate between colors and various shades of gray. The research is published in the psychology journal Learning and Behavior, volume 34 issue 2.
“My study shows that giant pandas have some sort of color vision,” said Kelling, graduate student in Georgia Tech’s Center for Conservation Behavior in the School of Psychology. “Most likely, their vision is dichromatic, since that seems to be the trend for carnivores.”

Vision is not a well-studied aspect of bears, including the giant pandas. It has long been thought that bears have poor vision, perhaps, Kelling said, because they have such excellent senses of smell and hearing. Some experts have thought that bears must have some sort of color vision as it would help them in identifying edible plants from the inedible ones, although there’s been little experimental evidence of this. However, one experiment on black bears found some evidence that bears could tell blue from gray and green from gray. Kelling used this study’s design as the basis to test color vision in Zoo Atlanta’s giant pandas.

Over a two-year period, Kelling investigated whether giant pandas can tell the difference between colors and shades of gray. In separate tests, the two pandas (Lun Lun, the female, and Yang Yang, the male) were presented with three PVC pipes, two hanging under a piece of paper that contained one of 18 shades of gray and one that contained a color – red, green or blue. If the panda pushed the pipe located under a color, it received a reward. If it pushed one of the pipes under the gray paper, it received nothing.

Kelling tested each color separately against gray. In the green versus gray tests, the bears’ performance in choosing green was variable, but mostly above chance. In the red versus gray tests, both bears performed above chance every single time. Only Lun Lun completed the blue versus green tests because Yang Yang had a tooth problem that prevented him from eating the treats used as reinforcement. For this trial, Lun Lun performed below chance only once.

“While this study shows that giant pandas have some color vision, it wasn’t conclusive as to what level of color vision they have,” said Kelling. “From this study, we can’t tell if the pandas can tell the difference between the colors themselves, like red from blue, or blue from green. But we can see that they can determine if something is gray or colored. That ability and the accompanying visual acuity could lead to the pandas being better able to forage for bamboo. For instance, to determine whether to head for a bamboo patch that is healthy and colorful as opposed to one that is brown and dying.”

http://www.gatech.edu/

Giant Panda Mating Season At National Zoo

2009-06-01T22:36:00.000-07:00

Zoo staff carefully observed each mating and, because satisfactory mating did not occur, Zoo scientists and veterinarians performed a nonsurgical artificial insemination Wednesday morning. Both pandas were anesthetized, allowing Zoo scientists to collect sperm from Tian Tian and insert it directly into Mei Xiang's uterus.

Giant pandas have one very brief breeding season per year, with only a day or two of actual mating.

Zoo staff separated Mei Xiang and Tian Tian prior to mating. Following mating, they will remain separated for the next few months, until Mei Xiang either delivers a cub, or until Zoo scientists determine that she is not pregnant. Keeping the pandas separated will reduce the risk of increased stress hormone levels in Mei Xiang, which could jeopardize ovulation, conception and implantation. Veterinarians will monitor Mei Xiang's hormone levels and perform ultrasounds to determine whether or not she is pregnant.

A team of experts from the National Zoo developed the comprehensive breeding plan for the Zoo's giant pandas. They took into consideration the genetic goals for the zoo population in addition to the welfare of each animal.

During 2007's breeding season, the National Zoo collaborated with the San Diego Zoo to use frozen semen from their male panda, Gao Gao (gow-GOW). As part of the breeding plan, he was considered again this year to be an ideal sperm donor for Mei Xiang. In February, Gao Gao was examined for signs of discomfort. A definitive cause could not be determined, but the panda's discomfort may be related to arthritis. Because his condition is still being monitored, scientists and veterinarians decided not to anesthetize him for semen collection and, instead, allow Mei Xiang to mate with Tian Tian.

This year's breeding is very similar to what took place in 2005, when scientists performed an artificial insemination after natural mating attempts between the two bears proved unsuccessful. That led to cub Tai Shan (tie-SHON), who was born July 9, 2005. He will remain at the National Zoo until some time after his fourth birthday, when he will be sent to a giant panda preserve in China.
http://www.si.edu/

Giant Panda Can Survive

2009-06-01T22:34:00.001-07:00

The giant panda is not at an "evolutionary dead end" and could have a long term viable future, according to new research involving scientists from Cardiff University.
Previous studies have found that the giant panda's isolation, unusual dietary requirements and slow reproductive rates have led to a lack of genetic diversity that will inevitably lead the species to extinction.

Now a study by Professor Michael Bruford and Dr Benoît Goossens from the School of Biosciences, in collaboration with Professor Fuwen Wei and colleagues from the Institute of Zoology along with the China West Normal University in Sichuan, has found that the decline of the species can be linked directly to human activities rather than a genetic inability to adapt and evolve.

"Our research challenges the hypothesis that giant panda's are at an 'evolutionary dead end'" said Professor Bruford. "It is however clear that the species has suffered demographically at the hands of human activities such as deforestation and poaching".

The study gives a new genetic perspective on the giant panda, as well as tracing its demographic history. The research also shows that in areas where habit conservation projects are in place, the giant panda is flourishing and population numbers are increasing.

"Our research suggests we have to revise our thinking about the evolutionary prospects for the giant panda" said Professor Bruford. "The species has a viable future and possesses the genetic capacity to adapt to new circumstances. Conservation efforts should therefore be directed towards habitat restoration and protection. In their natural environment, the giant panda is a species that can have a bright future."

The research is reported in the journal Molecular Biology and Evolution.

http://www.cardiff.ac.uk/

When Hosts Go Extinct, What Happens To Their Parasites

2009-06-01T22:33:00.001-07:00

Hands wring and teeth gnash over the loss of endangered species like the panda or the polar bear. But what happens to the parasites hosted by endangered species? And although most people would side with the panda over the parasite, which group should we worry about more?
In a new paper published in Proceedings of the Royal Society B, North Carolina State University biologist Rob Dunn and colleagues examine the concept of coextinction, or the domino effect of extinctions caused by species loss. For example, each fig species tends to be pollinated by a single fig wasp such that the loss of one should result in the loss of the other.

Mathematical models suggest that coextinctions due to the actions of humans are very common, the paper asserts. Yet, counterintuitively, there have been few reported cases of coextinction in the scientific literature.

"What we know about coextinctions presents a kind of paradox. The models suggest thousands of coextinctions have already occurred and that hundreds of thousands may be on the horizon. Yet we have observed few such events," Dunn says. "So we're not sure if all of these coextinctions are happening and not being tracked, or if parasites and mutualist species are better able to switch partners than we give them credit for, or something in between. Maybe some of the specialized relationships – like between the figs and fig wasps – aren't so specialized."

Moreover, Dunn says, the models, if crudely accurate, suggest that the number of parasite coextinctions greatly outweighs the number of host extinctions.

"Since the diversity of parasitic or affiliated species – which may include viruses, ticks, lice and bacteria, and butterflies, but also so-called mutualists such as the crops pollinated by honey bees or the bees themselves – is several orders of magnitude greater than that of their hosts, the numbers of coextinctions are also expected to be far greater than the number of extinctions of host species," Dunn says.

This numbers game alone presents strong evidence to suggest that coextinctions are more important than the original host extinctions themselves. But the paper also examines other costs of coextinction – including the losses of biological diversity, unique species traits and what we can learn about evolutionary history.

But, regardless of whether we care at all about the loss of such species and their traits and roles, there is something even scarier about the consequences of coextinction.

"There is a distinct possibility that declines in host species could drive parasite species to switch onto alternative hosts, which in turn could escalate the rate of emerging pathogens and parasites both for humans and our domesticated animals and plants," Dunn says. "Put simply, when a host becomes rare, its parasites and mutualists have two choices: jump ship to another host or go extinct. Either situation is a problem."

Dunn noted that the regions where new human diseases, such as bird flu, are emerging coincide with the regions where the most mammal and bird species are endangered. "We have long talked about the negative consequences of the endangerment of the species we love," he says, "but getting left with their parasites is a consequence no one bargained for."

The paper concludes by calling for better study and understanding of coextinction, and for documenting cases of coextinction when they are discovered. It also calls for more study into the interactive effects of the different reasons for extinction – habitat loss, species invasion, overkill and coextinctions, not to mention climate change – to gauge how they affect each other.

Oregon Bee Loves Berries

2009-06-01T22:30:00.001-07:00

Bringing grains of pollen to waiting blackberry and red raspberry blossoms may be the special talent of a small, emerald-green bee called Osmia aglaia. That's according to Agricultural Research Service entomologist James H. Cane, who—in outdoor experiments in Oregon and Utah—has studied the pollination prowess of this 3/8-inch-long bee perhaps more extensively than any other scientist.

The hardworking bee, native to Oregon and California, may help with pollination chores, augmenting the work of America's best-known crop pollinator, the European honey bee Apis mellifera.

In recent years, hived honey bees across the country have been hit hard by a mostly mysterious condition known as colony collapse disorder. That problem—and others caused by mites, beetles, diseases and Africanized honey bees—have added even more urgency to the need to find proficient pollinators among America's wild native bees, noted Cane.

He's based at the ARS Pollinating Insect Biology, Management and Systematics Research Unit in Logan, Utah. In one series of experiments, Cane showed that O. aglaia bees work quickly, visiting just as many red raspberry flowers, and nearly as many blackberry blossoms, as do honey bees, in the same amount of time.

Both kinds of berries are mostly self-pollinating, meaning that they can form fruit without the need for insects to bring pollen to them. But better berries result if honey bees or O. aglaia visit red raspberry flowers, Cane found. The plump, well-formed fruits were 30 percent bigger than those on red raspberry plants not visited by either bee species.

Commercial Bees Spreading Disease To Wild Pollinating Bees

2009-06-01T22:29:00.001-07:00

Bees provide crucial pollination service to numerous crops and up to a third of the human diet comes from plants pollinated by insects. However, pollinating bees are suffering widespread declines in North America and scientists warn that this could have serious implications for agriculture and food supply. While the cause of these declines has largely been a mystery, new research reveals an alarming spread of disease from commercial bees to wild pollinators.

Michael Otterstatter and James Thomson of the University of Toronto have presented compelling evidence in a new study that commercially produced bumble bees used in greenhouses are infecting their wild cousins, and that this is likely contributing to reductions in the natural pollinating bee population.

Otterstatter and Thomson investigated the occurrence of disease in wild bumble bees in southern Ontario, Canada, particularly in areas close to industrial greenhouse operations. In addition, the authors used a combination of laboratory experiments and mathematical modelling to simulate the spread, or 'spillover', of disease from commercial bees to wild populations, and to predict the extent and severity of such spread in the wild.

The researchers found that commercial bumble bees often carry a harmful and highly contagious pathogen, Crithidia bombi, and that these bees regularly escape from greenhouses and interact with wild bees at flowers. Near greenhouses, the rates of infection were startling: up to one half of wild bumble bees were infected with C. bombi, whereas no bees harboured this pathogen at sites away from greenhouses.

Furthermore, the frequency and severity ofinfections declined with increasing distance from greenhouses, suggesting that these agricultural operations are foci of disease for wild pollinators.

The mathematical model that Otterstatter and Thomson developed confirmed that pathogen spillover from commercial bees would allow diseaseto invade wild pollinator populations near greenhouses. The model predicts that, although disease may build up slowly at first, given sufficient time, spillover will result in a large-scale epidemic among wild bees.

The commercial bumble bee industry is expanding worldwide. The abundance of disease in commercial bees, and the international trafficking of infected hives, may pose a substantial threat to wild bee pollinators. The authors emphasize that improved management of domestic bees through, for example, greater attention to their diseases and their overlap with wild species, would greatly reduce, or even eliminate, pathogen spillover.

Wild Bees Make Honeybees Better Pollinators

2009-06-01T22:28:00.001-07:00

Up to a third of our food supply depends on pollination by domesticated honeybees, but the insects are up to five times more efficient when wild bees buzz the same fields, according to a study published Aug. 28 in the journal Proceedings of the National Academy of Sciences of the USA.

"As honeybees become more scarce, it becomes more important to have better pollinators," said Sarah Greenleaf, a postdoctoral researcher at UC Davis and first author on the study.

As a graduate student at Princeton University, Greenleaf carried out a two-year study of honeybees used to pollinate sunflower crops on farms in Yolo County, Calif., near UC Davis.

Compared to honeybees, wild bees did not contribute much directly to crop pollination. But on farms where wild bees were abundant, honeybees were much more effective in pollinating flowers and generating seeds, Greenleaf found.

There appear to be two reasons for that. Male wild bees, probably looking for mates, will latch onto worker honeybees, which are sterile females, causing them to move from one flower to another. Secondly, female wild bees appear to "dive bomb" honeybees, forcing them to move. Frequent movement between flowers spreads pollen around more effectively.

Greenleaf and her co-author Claire Kremen, now a professor at UC Berkeley, calculated that wild bees contributed about $10 million of value to the $26-million sunflower industry alone.

All the fields in the study were conventionally farmed, but varied in their proximity to natural habitat, Greenleaf said.

How Bees Hold Onto Flowers

2009-06-01T22:27:00.001-07:00

When bees collect nectar, how do they hold onto the flower? Cambridge University scientists have shown that it is down to small cone-shaped cells on the petals that act like 'velcro' on the bees' feet.

New research shows that bumblebees can recognise the texture of petal surfaces by touch alone. More importantly, they choose to land on petals with conical cells that make it easier to grip, rather than on flat, smooth surfaces. With this extra grip, they can extract nectar from the flower more efficiently.

In the natural world, bees can take visual or olfactory cues without needing to land on the flower itself. Their ability to identify conical-celled surfaces by touch would therefore seem to be of limited use in terms of flower recognition. The researchers, led by Beverley Glover, wondered whether the conical cells play a different role by providing better grip on an otherwise slippery plant surface, thereby making nectar collection easier for the bees.

To test this, the researchers used artificial flowers cast from epoxy resin, half with conical cells and half with flat surfaces. When these casts were horizontal, the bees showed no preference, visiting each type roughly half the time. However, once the angle of the cast increased, so did the bees' preference for the conical cells. When these casts were vertical, the bees visited the conical-celled ones over 60% of the time.

The researchers, who were funded by the Natural Environment Research Council (NERC), were able to visualise why the bees preferred conical cells. Using high-speed video photography they saw that when bees attempted to land on the flat-celled epoxy petals they would scramble for grip, rather like a climber struggling to find a foothold on an ice-covered cliff. However, on the conical-celled casts the bees were always able to find grip, stop beating their wings and feed on the flower.

The next step was to establish whether bees in the natural world actually preferred real flowers with conical cells. To test this, the researchers used snapdragon plants, which have conical petal cells, and mutant snapdragons, lacking such cells. When the flowers were horizontal and required little handling the bees would visit the conical-celled flowers 50% of the time. However when the flowers were vertical and required complex handling the bees learnt to recognise the conical-celled flowers and landed on them 74% of the time.

Around 80% of flowers have these conical cells and the researchers believe that all pollinators that land on flowers (such as butterflies, flies and other kinds of bee) may have a preference for petals with a rough surface.

Beverley Glover said: "For bees to maintain their balance and hold onto a flower is no easy task, especially in windy or wet conditions. It's great to see that evolution has come up with the simple solution of equipping flowers with a Velcro-like surface that bees can get a grip on".

Mosquito Evolution Spells Trouble For Galapagos Wildlife

2009-06-01T22:26:00.000-07:00

The Galapagos giant tortoise and other iconic wildlife are facing a new threat from disease, as some of the islands' mosquitoes develop a taste for reptile blood.

Scientists from the University of Leeds, the Zoological Society of London (ZSL) and the Galapagos National Park have discovered that while its mainland ancestors prefer the blood of mammals and the occasional bird, the Galapagos form of the black salt marsh mosquito (Aedes taeniorhynchus) has shifted its behaviour to feed mainly on reptiles – primarily Galapagos giant tortoises and marine iguanas.

The findings raise fears that these changes could devastate the islands' unique native wildlife if a new mosquito-borne disease is introduced - a scenario which is increasingly likely with the continuing rise in tourism.

Using genetic techniques, the researchers showed that the mosquito colonised the Galapagos around 200,000 years ago and was not introduced by humans as previously thought, giving them time to adapt to conditions in Galapagos. They have also found that unlike the mainland populations that normally live in mangroves and salt marshes along the coast, the Galapagos form of the mosquito can also breed up to 20 km inland and at altitudes of up to 700 metres. The research team believe the shift in feeding behaviour is an adaptation to life in Galapagos, since the islands had few mammal species prior to the arrival of Man some 500 years ago.

"When we started the work we thought that this species was also introduced by humans, so it was a surprise that it turned out to be so ancient," says Arnaud Bataille, the University of Leeds and ZSL PhD student who carried out the work. "The genetic differences of the Galapagos mosquitoes from their mainland relatives are as large as those between different species, suggesting that the mosquito in Galapagos may be in the process of evolving into a new species."

Mosquitoes are known to transmit important wildlife diseases, such as avian malaria and West Nile fever. While there is no evidence that such diseases are currently present on Galapagos, the widespread presence of the mosquito, and the fact that it feeds on a broad range of the native species, means that any new disease that arrives from the continent could spread rapidly to a wide variety to wildlife throughout the islands. Due to its long isolation, Galapagos wildlife is not likely to have much immunity to new diseases, so the effects could be devastating.

"With tourism growing so rapidly the chance of a disease-carrying mosquito hitching a ride from the mainland on a plane is also increasing, since the number of flights grows in line with visitor numbers" says Dr Andrew Cunningham, from the Zoological Society of London, one of the authors of the study. "If a new disease arrives via this route, the fear is that Galapagos' own mosquitoes would pick it up and spread it throughout the archipelago."

Rather than implementing control measures against Galapagos' own unique mosquito, the research team argues that it is imperative that measures are taken to avoid introducing new diseases to the islands.

The Ecuadorian government recently introduced a requirement for planes flying to Galapagos to have a residual insecticide treatment on the interior surfaces, and spraying in the hold and cabin on each flight. However, similar controls are yet to be implemented for ships.

Co-author Dr Simon Goodman, of Leeds' Faculty of Biological Sciences says: "It is absolutely vital that these control measures are maintained and carried out rigorously, otherwise the consequences could be very serious indeed."

Unraveling Lion's Natural History

2009-05-29T06:17:00.001-07:00

The lion (Panthera leo) is one of the world's most charismatic carnivores. In an article published November 7 in the open-access journal PLoS Genetics, an international team of researchers provides insights into the genetic structure and history of lion populations.

Their work refutes the hypothesis that African lions consist of a single, randomly breeding (panmictic) population. It also indicates the importance of preserving populations in decline as opposed to prioritizing larger-scale conservation efforts.

Understanding the broader aspects of the evolutionary history of the lion has been hindered by a lack of comprehensive sampling and appropriately informative genetic markers. Nevertheless, the unique social ecology of lions and the well-documented infectious diseases they have experienced, including lion-specific feline immunodeficiency virus (FIVPle), provides the opportunity to study lion evolutionary history using both host and virus genetic information.

In total, a comprehensive sample of 357 individuals from most of the major lion populations in Africa and Asia were studied. The authors compared the large multigenic dataset from lions with patterns of genetic variation of FIVPle to characterize the genomic legacy of lion populations.

The research reveals evidence of unsuspected genetic diversity even in the well-studied lion population of the Serengeti ecosystem, which consists of recently admixed animals derived from three distinct genetic groups.

Lion Feline Immunodeficiency Virus

2009-05-29T06:14:00.001-07:00

Parts of feline immunodeficiency virus (FIV) isolated from wild lions have undergone substantial genetic recombination, says new research. The sequencing of the two full FIV genomes of different lion subtypes shows the importance of whole-genome analysis in understanding complex genetic events. These findings will be relevant to big cat conservation and developing more effective animal models for HIV.

FIV is a member of the lentivirus family of retroviruses, as is HIV. The feline virus causes similar disease progression to HIV in domestic cats, and is used by researchers as an animal model for human disease.

FIV also infects a number of other cat species, many of which are endangered. The virulence and pathogenicity of the virus varies between species, but the genetic contribution to this variation is unclear. Full-length viral genome sequences are vital for scientists to understand the extent of genetic involvement yet, until recently, only six species-specific strains of FIV had been sequenced in full: Pallas cat, domestic cat (subtypes A, B and C) and puma (subtypes A and B).

Now, Jill Pecon-Slattery and Stephen J. O'Brien from the National Cancer Institute's Center for Cancer Research in Frederick, MD, USA and colleagues from the USA and Botswana have sequenced the genomes of two lion FIV subtypes in full: FIVPle subtype B, isolated from lions in the Serengeti National Park in Tanzania, and FIVPle subtype E, isolated from lions in the Okavango Delta in Botswana. Using comparative genomics methods the team found that the two viral subtypes shared a common evolutionary history -- confirming earlier research that suggested FIV has evolved in a species-specific manner.

However, the lion viruses showed substantial variation in the env gene region, which encodes the envelope glycoprotein essential for viral binding and entry. Lion virus subtype E was more closely related to domestic cat virus than to lion subtype B or Pallas cat virus. The researchers suggest this is due to recombination between strains in the wild, either involving an unidentified lion FIV strain or a strain from another African cat species.

The authors write: "The changes observed in the env gene as a consequence of recombination in FIVPle will provide important clues to the natural history of these viruses and their hosts, and may lead to insights into genetic determinants of pathogenicity and virulence differences between domestic cat and lion FIV; findings with important implications for HIV pathogenesis in humans and virus attenuation in wild populations of endangered species."

http://www.biomedcentral.com/bmcgenomics/

Choosing Dry Or Wet Food For Cats

2009-05-29T06:13:00.000-07:00

Although society is accustomed to seeing Garfield-sized cats, obese, middle-aged cats can have a variety of problems including diabetes mellitus, which can be fatal. The causes of diabetes mellitus in cats remain unknown, although there has been a strong debate about whether a dry food diet puts cats at greater risk for diabetes. A new study from a University of Missouri-Columbia veterinarian suggests that weight gain, not the type of diet, is more important when trying to prevent diabetes in cats.

Because dry cat food contains more starch and more carbohydrates than canned cat food, some have argued that a diet containing large amounts of carbohydrates is unnatural for a cat that is anatomically and physiologically designed to be a carnivore. Carbohydrates constitute between 30 percent and 40 percent of dry cat food. Some have been concerned that this unnatural diet is harmful to cats and leads to increased incidence of diabetes. Wet cat food, on the other hand, is high in protein and more similar to a natural carnivore diet.

In the study, Robert Backus, assistant professor and director of the Nestle Purina Endowed Small Animal Nutrition Program at MU, and his team of researchers compared a colony of cats in California raised on dry food with a colony of cats in New Zealand raised on canned food. After comparing glucose-tolerance tests, which measures blood samples and indicates how fast glucose is being cleared from the blood after eating, researchers found no significant difference between a dry food diet and a wet food diet.

They also compared the results between cats less than three years of age and cats older than three. The MU veterinarian indicated that allowing cats to eat enough to become overweight is more detrimental to their health than the type of food they eat.

"Little bits of too much energy lead to weight gain overtime," Backus said. "We did find that cats on canned or wet food diets have less of a tendency towards obesity than cats on dry food diets."

Forty percent of all cats in middle age are overweight or obese. According to Backus, male cats should weigh between 10 and 11 pounds, and female cats should weigh between 5.5 and 7.7 pounds. Besides diabetes, overweight cats are prone to other conditions such as skin diseases, oral diseases and certain cancers. When cats are spayed and neutered, they have a tendency to eat more and gain weight. Backus suggests monitoring the food even more closely at this time and not allowing the cat to eat in excess.

"The most effective thing you can do is be the one who determines how much your cat eats," Backus said. "We have been conditioned to fat cats, but cats should have only between 18 percent to 20 percent body fat."

Backus' research was presented recently at the American College of Veterinary Internal Medicine Conference in Seattle.

http://www.missouri.edu/

Cats Do Suffer From Arthritis

2009-05-29T06:11:00.000-07:00

New research at the University of Glasgow has found that arthritis in cats is far more common than previously thought.

Professor David Bennett in the University’s Vet School, has found that as many as 30 per cent of all cats over the age of eight may be suffering in pain and a reduced quality of life due to arthritis. It has been supposed cats do not suffer from this disease because their symptoms are less prominent than in other species.

Professor Bennett said: “One of the problems has been in recognizing the signs of arthritis in cats and we have always assumed these are the same as in other animals. Arthritis is often a very painful condition and it is always difficult to detect and quantify pain in animals and cats in particular, but what we do know is that cats with arthritis will generally not limp as a dog or as a horse might do. Also, their joints may not be particularly thickened and crepitus and effusion are rare, again different to other animals. It is also unusual for them to vocalize their pain but this does not mean that cats suffer from arthritis any less frequently than dogs and other animals”.

A recent study of cats with osteoarthritis by Professor Bennett and his team found that the key to recognising pain in cats is to check for any lifestyle changes which may result from mobility issues. These could include an unwillingness to jump or an inability to jump as high as previously, and a reduction in the cats overall activity levels, such as, sleeping more and hunting and playing less. Because cats often exercise out of sight of their owners, abnormalities in their gait can be difficult to spot."

Professor Bennett continued: “In my view, the owner is critical to the diagnostic process. They just have to be asked the right questions. There is undoubtedly a lack of awareness by owners that their cats can suffer from arthritis and they assume that these lifestyle changes such as an unwillingness to jump are just a reflection of ‘getting old’. However, these cats are in significant pain and when given appropriate treatment, they can once again enjoy a much better quality of life, in many cases getting back to their old self.

“Fortunately the emergence of arthritis in cats as a major clinical problem is now being taken much more seriously and pharmaceutical companies are now putting much more effort into developing medicines for treating this unpleasant disease in cats.”

There are currently nine million cats in the UK and a quarter of all households now own at least one cat. This figure is set to grow with cats starting to overtake dogs in numbers possibly due to more single occupancy households and owners with busy lifestyles.

Cats suffer with arthritis as a result of increasing ‘wear and tear’ due to age or as a consequence of previous injury to the skeleton or due to some developmental abnormality of the skeleton which they may have been born with. This eventually results in chronic pain and a significant reduction in the quality of life of the cat.

http://www.gla.ac.uk/

Stressed-out Cats

2009-05-29T06:09:00.001-07:00

Cats, like humans, can develop stress-related illness, University of Edinburgh experts have found. Significant life-changes like moving house or the arrival of a new member of the family can lead to bladder problems in some cats, say the animal specialists. But the biggest stressor of all for a cat is when it doesn't get along with other cats in the house, studies have shown.

Cat health professionals at the University's Hospital for Small Animals studied the lifestyles of a group of cats with no apparent physical cause for their bladder problems and compared them with a control group of disease-free cats. They found that the sick cats were generally more anxious, and were particularly stressed by being in conflict with other cats in the house.

Dr Danielle Gunn-Moore, the Nestlé Purina senior lecturer in feline medicine at the University of Edinburgh Royal (Dick) School of Veterinary Studies, explained: "Feline lower urinary tract disease (FLUTD) is a group of diseases of the bladder, most commonly seen in pedigree, middle-aged, overweight male cats which take little exercise, use an indoor litter box, don't go out much and eat a dry food diet.

"This condition is particularly frustrating for vets and owners, because most cases have no apparent cause, and are categorised as feline idiopathic cystitis (FIC). Earlier studies led us to believe that stress could be a trigger factor for FIC, and we wanted to identify differences in the cats' environments and temperaments which might be causing this condition."

This latest, questionnaire-based study compared 31 cats with FIC to 24 cats in the same households that did not have cystitis. These were in turn compared with a control group of 125 healthy cats.

Dr Gunn-Moore said: " Although many owners of cats taking part in the study reported that a fear of strangers was the most common problem they observed, this tends to be a short-term stressor. If a cat is living with another cat where there is a conflict, this is a chronic situation causing long-term stress. We concluded that this is a significant factor in the development FIC, and will be carrying out further studies to see how best this and other stress factors can be overcome."

Dr Gunn-Moore recommends that cats that have FLUTD or FIC should be fed wet food, and encouraged to drink more fluid. This can be done, for example, by adding tuna-flavoured ice-cubes to water, or offering water fountains to encourage them to drink.

A small, separate pilot study by Dr Gunn-Moore's team used a synthetic soothing scent to reduce anxiety showed a trend for cats exposed to the scent to have fewer episodes of FIC. More work will continue on this study.

Asthmatic Cats May Be Allergic To Humans

2009-05-29T06:08:00.001-07:00

In a complete turnaround, instead of pets being blamed for causing allergies and breathing problems amongst people, human lifestyles are potentially triggering asthma attacks in cats. Cigarette smoke, dusty houses, human dandruff, pollen and certain types of cat litters can all create inflammation in cats' airways and worsen asthma. Now, in a first study of its type in the UK, feline clinicians at the University of Edinburgh's Hospital for Small Animals will look at the part played by a specific bacteria found in the lungs of asthmatic cats, with a view to improving treatments.

Feline asthma is a common disease, with around one in 200 cats suffering from the condition, which causes cough, wheeze and shortness of breath. Pedigree oriental breeds like Siamese cats are more prone to the disease, and the disease is worsened by household irritants.

Nicki Reed, Feline Advisory Bureau senior clinical scholar at the Royal (Dick) School of Veterinary Studies, based at the University's Hospital for Small Animals, explained: "Cats with feline asthma syndrome can be made worse by living in a household where people smoke, or where there are other potential allergens or irritants. We find that bringing asthmatic cats into the hospital here and removing them from the standard 'triggers' like dust and smoke can improve their condition. Also, changing cat litter from granules to a newspaper-based product can help some asthmatic animals."

Recent work in the field of human asthma has suggested a link between bacterial Mycoplasma infection and a worsening of asthmatic symptoms. Research in the United States and Australia has shown this bacterium is present in a fifth of all lung fluid samples from asthmatic cats. The Edinburgh team now seek to study 50 cats with asthma to identify the incidence of this bacterial infection in the UK and improve treatments. The cats will be sent to the Hospital by referring vets.

Cats Can Succumb To Feline Alzheimer's Disease

2009-05-29T06:07:00.000-07:00

Aging cats can develop a feline form of Alzheimer's disease, a new study reveals. Scientists at the Universities of Edinburgh, St Andrews, Bristol and California have identified a key protein which can build up in the nerve cells of a cat's brain and cause mental deterioration.

In humans with Alzheimer's disease, this protein creates 'tangles' inside the nerve cells which inhibit messages being processed by the brain. The team says that the presence of this protein in cats is proof that they too can develop this type of disease.

By carrying out post-mortem examination of cats which have succumbed naturally to the disease, scientists may now be able to uncover vital clues about how the condition develops. This may eventually help scientists to come up with possible treatments.

Scientists already thought cats were susceptible to dementia because previous research had identified thick, gritty plaques on the outside of elderly cats' brain cells which are similar to those found in humans. But, by pinpointing this second key marker, the Edinburgh-led team says we can be sure that cats can suffer from a feline form of Alzheimer's.

Dr Danielle Gunn-Moore, at the University of Edinburgh's Royal (Dick) School of Veterinary Studies, said: "This newly discovered protein is crucial to our understanding of the aging process in cats. We've known for a long time that cats develop dementia, but this study tells us that the cat's neural system is being compromised in a similar fashion to that we see in human Alzheimer's sufferers. The gritty plaques had only hinted that might be the case -- now we know.

"The shorter life-span of a cat, compared to humans, allows researchers to more rapidly assess the effects of diet, high blood pressure, and prescribed drugs on the course of the disease. However, we also need to understand more about our geriatric cats for their own benefit, so we can slow down the degeneration the disease brings and keep them as happy cats for as long as possible."

"As with humans, the life expectancy of cats is increasing and with this longer life runs the greater chance of developing dementia. Recent studies suggest that 28% of pet cats aged 11-14 years develop at least one old-age related behaviour problem and this increases to more than 50% for cats over the age of 15."

Experts suggest that good diet, mental stimulation and companionship can reduce the risk of dementia in both humans and cats. Dr Gunn Moore explained: "If humans and their cats live in a poor environment with little company and stimulation, they are both at higher risk of dementia. However, if the owner plays with the cat, it is good for both human and cat. A good diet enriched with antioxidants is also helpful in warding off dementia, so a cat owner sharing healthy meals like chicken and fish with their pet will benefit them both."

Dr Frank Gunn-Moore, at the School of Biology, University of St Andrews, said: "This work relied on a team effort with the different skills and expertise from our different institutions. It has given us an insight into the molecular changes that are occurring in the degenerating brain. From this knowledge we are now currently trying to develop new and novel treatments which will be able to help both cats and humans".

The findings of the study are published in a recent edition of the Journal of Feline Medicine.

http://www.ed.ac.uk/home

Cats' Eye Diseases Genetically Linked To Diseases In Humans

2009-05-29T06:06:00.000-07:00

About one in 3,500 people are affected with retinitis pigmentosa (RP), a disease of the retina's visual cells that eventually leads to blindness. Now, a University of Missouri researcher has identified a genetic link between cats and humans for two different forms of RP. This discovery will help scientists develop gene-based therapies that will benefit both cats and humans.

"The same genetic mutations that cause retinal blindness in humans also cause retinal blindness in cats," said Kristina Narfstrom, the Ruth M. Kraeuchi-Missouri Professor in Veterinary Ophthalmology in the MU College of Veterinary Medicine. "Now, cats with these mutations can be used as important animal models to evaluate the efficiency of gene therapy. In addition, the eye is an ideal organ to use as we examine the potential of gene replacement intervention because it offers an accessible and confined environment."

Researchers examined the genetic mutations in two groups of cats; one with a congenital form of RP and another with a late-onset form and were able to identify the genes responsible for both forms of the disease in cats. In the study, researchers found that cats with the late-onset form of the disease have a mutation in the CEP290 gene, which is the same mutation found in humans with Joubert syndrome and Leber's congenital amaurosis. In both of these diseases, the genetic mutations result in changes in the function and structure of the photoreceptors. A photoreceptor is a nerve cell found in the eye's retina that is capable of phototransduction, or the process by which light is converted into electrical signals. The changes in the photoreceptors result in cell death, which lead to blindness.

"Cats are excellent models because they have relatively large eyes that are comparable to those of human babies. The retinal changes that occur and the progression to blindness in cats is similar to what happens in the human disease," Narfstrom said. "As a surgeon, I can use the same treatment methods and tools in cats that they use in humans."

Human autosomal recessive RP is among the most common cause of retinal degeneration and blindness, with no therapeutic intervention available. Initially it leads to night blindness, then loss of peripheral vision and, with progression, there is also a loss of central vision.

Like humans, Abyssinian cats with the CEP290 mutation have normal vision at birth but develop early changes in the interior of their eyes by the time they are approximately 2 years old. The cats with the congenital form of the disease are blind from birth with severe changes in the interior of their eyes after only a couple of months.

In May, Narfstrom will present her latest findings during the Association for Research in Vision and Ophthalmology 2009 Annual Meeting in Fort Lauderdale, Fla. An earlier study, "Mutation in CEP290 Discovered for Cat Model of Human Retinal Degeneration," was published in the Journal of Heredity.

http://www.missouri.edu/

Cats' Central Nervous System Can Repair Itself

2009-05-29T06:04:00.001-07:00

Scientists studying a mysterious neurological affliction in cats have discovered a surprising ability of the central nervous system to repair itself and restore function.

In a study published March 30, 2009 in the Proceedings of the National Academy of Sciences, a team of researchers from the University of Wisconsin-Madison reports that the restoration in cats of myelin — a fatty insulator of nerve fibers that degrades in a host of human central nervous system disorders, the most common of which is multiple sclerosis — can lead to functional recovery.

"The fundamental point of the study is that it proves unequivocally that extensive remyelination can lead to recovery from a severe neurological disorder," says Ian Duncan, the UW-Madison neuroscientist who led the research. "It indicates the profound ability of the central nervous system to repair itself."

The finding is important because it underscores the validity of strategies to reestablish myelin as a therapy for treating a range of severe neurological diseases associated with the loss or damage of myelin, but where the nerves themselves remain intact.

Myelin is a fatty substance that forms a sheath for nerve fibers, known as axons, and facilitates the conduction of nerve signals. Its loss through disease causes impairment of sensation, movement, cognition and other functions, depending on which nerves are affected.

The new study arose from a mysterious affliction of pregnant cats. A company testing the effects on growth and development in cats using diets that had been irradiated reported that some cats developed severe neurological dysfunction, including movement disorders, vision loss and paralysis. Taken off the diet, the cats recovered slowly, but eventually all lost functions were restored.

"After being on the diet for three to four months, the pregnant cats started to develop progressive neurological disease," says Duncan, a professor of medical sciences at the UW-Madison School of Veterinary Medicine and an authority on demyelinating diseases. "Cats put back on a normal diet recovered. It's a very puzzling demyelinating disease."

The afflicted cats were shown to have severe and widely distributed demyelination of the central nervous system, according to Duncan. And while the neurological symptoms exhibited by the cats are similar to those experienced by humans with demyelination disorders, the malady does not seem to be like any of the known myelin-related diseases of humans.

In cats removed from the diet, recovery was slow, but all of the previously demyelinated axons became remyelinated. The restored myelin sheaths, however, were not as thick as healthy myelin, Duncan notes.

"It's not normal, but from a physiological standpoint, the thin myelin membrane restores function," he says. "It's doing what it is supposed to do."

Knowing that the central nervous system retains the ability to forge new myelin sheaths anywhere the nerves themselves are preserved provides strong support for the idea that if myelin can be restored in diseases such as multiple sclerosis, it may be possible for patients to regain lost or impaired functions: "The key thing is that it absolutely confirms the notion that remyelinating strategies are clinically important," Duncan says.

The exact cause of the neurological affliction in the cats on the experimental diet is unknown, says Duncan, who was not involved in the original study of diet.

"We think it is extremely unlikely that [irradiated food] could become a human health problem," Duncan explains. "We think it is species specific. It's important to note these cats were fed a diet of irradiated food for a period of time."

In addition to Duncan, authors of the new PNAS study include Alexandra Brower of the Wisconsin Veterinary Diagnostic Laboratory; Yoichi Kondo and Ronald Schultz of the UW-Madison School of Veterinary Medicine; and Joseph Curlee, Jr. of Harlan Laboratories in Madison.

How Well Do Dogs See At Night?

2009-05-29T06:02:00.001-07:00

A lot better than we do, says Paul Miller, clinical professor of comparative ophthalmology at University of Wisconsin-Madison.

“Dogs have evolved to see well in both bright and dim light, whereas humans do best in bright light. No one is quite sure how much better a dog sees in dim light, but I would suspect that dogs are not quite as good as cats,” which can see in light that’s six times dimmer than our lower limit. Dogs, he says, “can probably see in light five times dimmer than a human can see in.”

Dogs have many adaptations for low-light vision, Miller says. A larger pupil lets in more light. The center of the retina has more of the light-sensitive cells (rods), which work better in dim light than the color-detecting cones. The light-sensitive compounds in the retina respond to lower light levels. And the lens is located closer to the retina, making the image on the retina brighter.

But the canine’s biggest advantage is called the tapetum. This mirror-like structure in the back of the eye reflects light, giving the retina a second chance to register light that has entered the eye. “Although the tapetum improves vision in dim light, it also scatters some light, degrading the dog’s vision from the 20:20 that you and I normally see to about 20:80,” Miller says.

The tapetum also causes dog eyes to glow at night.

Dogs Can Classify Complex Photos

2009-05-29T06:01:00.001-07:00

Like us, our canine friends are able to form abstract concepts. Friederike Range and colleagues from the University of Vienna in Austria have shown for the first time that dogs can classify complex color photographs and place them into categories in the same way that humans do. And the dogs successfully demonstrate their learning through the use of computer automated touch-screens, eliminating potential human influence.

In order to test whether dogs can visually categorize pictures, and transfer their knowledge to new situations, four dogs were shown landscape and dog photographs, and expected to make a selection on a computer touch-screen.

In the training phase, the dogs were shown both the landscape and dog photographs simultaneously and were rewarded with a food pellet if they selected the dog picture (positive stimulus). The dogs then took part in two tests.

In the first test, the dogs were shown completely different dog and landscape pictures. They continued to reliably select the dog photographs, demonstrating that they could transfer their knowledge gained in the training phase to a new set of visual stimuli, even though they had never seen those particular pictures before.

In the second test, the dogs were shown new dog pictures pasted onto the landscape pictures used in the training phase, facing them with contradictory information: on the one hand, a new positive stimulus as the pictures contained dogs even though they were new dogs; on the other hand, a familiar negative stimulus in the form of the landscape.

When the dogs were faced with a choice between the new dog on the familiar landscape and a completely new landscape with no dog, they reliably selected the option with the dog. These results show that the dogs were able to form a concept i.e. ‘dog’, although the experiment cannot tell us whether they recognized the dog pictures as actual dogs.

The authors also draw some conclusions on the strength of their methodology: “Using touch-screen computers with dogs opens up a whole world of possibilities on how to test the cognitive abilities of dogs by basically completely controlling any influence from the owner or experimenter.” They add that the method can also be used to test a range of learning strategies and has the potential to allow researchers to compare the cognitive abilities of different species using a single method.

http://www.springer.com/?SGWID=5-102-0-0-0

Dogs Feel Envy

2009-05-29T05:58:00.001-07:00

Experiments with various species have shown that monkeys often express resentful behavior when a partner receives a greater reward for performing an identical task. Monkeys have been shown to stage strikes, refusing to participate and ignoring what they perceive as inferior compensation. Dogs are capable of similar, though less sensitive, discrimination, report Friederike Range and colleagues.

The researchers conducted experiments with pairs of domestic dogs accompanied by their owners. While the partner and subject dogs sat next to each other with their owner standing behind them, each dog was prompted to put its paw in the experimenter's hand, and upon complying, given a piece of sausage or bread.

Compared to a variety of control situations, the dogs reacted differently to unfair reward distribution, as measured by their reaction when the partner was given food for the task, but the subject was not. This resentment was quantified in the number of times the experimenters had to prompt the animals, or the number of times the dog would perform the task before refusing. The dogs did not appear to care exactly what reward they were given, or whether the partner did or did not have to perform the task before receiving food.

Dog envy may be an evolutionary precursor to more sophisticated primate emotion, the researchers say.

http://www.pnas.org/

Using 'Dominance' To Explain Dog Behavior Is Old Hat

2009-05-29T05:57:00.001-07:00

A new study shows how the behaviour of dogs has been misunderstood for generations: in fact using misplaced ideas about dog behaviour and training is likely to cause rather than cure unwanted behaviour. The findings challenge many of the dominance related interpretations of behaviour and training techniques suggested by current TV dog trainers.

Contrary to popular belief, aggressive dogs are NOT trying to assert their dominance over their canine or human “pack”, according to research published by academics at the University of Bristol’s Department of Clinical Veterinary Sciences in the Journal of Veterinary Behavior: Clinical Applications and Research.

The researchers spent six months studying dogs freely interacting at a Dogs Trust rehoming centre, and reanalysing data from studies of feral dogs, before concluding that individual relationships between dogs are learnt through experience rather than motivated by a desire to assert “dominance”.

The study shows that dogs are not motivated by maintaining their place in the pecking order of their pack, as many well-known dog trainers preach.

Far from being helpful, the academics say, training approaches aimed at “dominance reduction” vary from being worthless in treatment to being actually dangerous and likely to make behaviours worse.

Instructing owners to eat before their dog or go through doors first will not influence the dog’s overall perception of the relationship – merely teach them what to expect in these specific situations. Much worse, techniques such as pinning the dog to the floor, grabbing jowls, or blasting hooters at dogs will make dogs anxious, often about their owner, and potentially lead to an escalation of aggression.

Dr Rachel Casey, Senior Lecturer in Companion Animal Behaviour and Welfare at Bristol University, said: “The blanket assumption that every dog is motivated by some innate desire to control people and other dogs is frankly ridiculous. It hugely underestimates the complex communicative and learning abilities of dogs. It also leads to the use of coercive training techniques, which compromise welfare, and actually cause problem behaviours.

“In our referral clinic we very often see dogs which have learnt to show aggression to avoid anticipated punishment. Owners are often horrified when we explain that their dog is terrified of them, and is showing aggression because of the techniques they have used – but its not their fault when they have been advised to do so, or watched unqualified ‘behaviourists’ recommending such techniques on TV.”

At Dogs Trust, the UK’s largest dog welfare charity, rehoming centre staff see the results of misguided dog training all the time. Veterinary Director Chris Laurence MBE, added: “We can tell when a dog comes in to us which has been subjected to the ‘dominance reduction technique’ so beloved of TV dog trainers. They can be very fearful, which can lead to aggression towards people.

“Sadly, many techniques used to teach a dog that his owner is leader of the pack is counter-productive; you won’t get a better behaved dog, but you will either end up with a dog so fearful it has suppressed all its natural behaviours and will just do nothing, or one so aggressive it’s dangerous to be around.”

Why Coral Reefs Around The World Are Collapsing

2009-05-29T05:55:00.001-07:00

An explosion of knowledge has been made in the last few years about the basic biology of corals, researchers say in a new report, helping to explain why coral reefs around the world are collapsing and what it will take for them to survive a gauntlet of climate change and ocean acidification.

Corals, it appears, have a genetic complexity that rivals that of humans, have sophisticated systems of biological communication that are being stressed by global change, and are only able to survive based on proper function of an intricate symbiotic relationship with algae that live within their bodies.

After being a highly successful life form for 250 million years, disruptions in these biological and communication systems are the underlying cause of the coral bleaching and collapse of coral reef ecosystems around the world, scientists report in the journal Science.

The research was funded in part by the National Science Foundation.

"We've known for some time the general functioning of corals and the problems they are facing from climate change," said Virginia Weis, a professor of zoology at Oregon State University. "But until just recently, much less has been known about their fundamental biology, genome structure and internal communication. Only when we really understand how their physiology works will we know if they can adapt to climate changes, or ways that we might help."

Corals are tiny animals, polyps that exist as genetically identical individuals, and can eat, defend themselves and kill plankton for food. In the process they also secrete calcium carbonate that becomes the basis for an external skeleton on which they sit. These calcified deposits can grow to enormous sizes over long periods of time and form coral reefs – one of the world's most productive ecosystems, which can harbor more than 4,000 species of fish and many other marine life forms.

But corals are not really self sufficient. Within their bodies they harbor highly productive algae – a form of marine plant life – that can "fix" carbon, use the energy of the sun to conduct photosynthesis and produce sugars.

"Some of these algae that live within corals are amazingly productive, and in some cases give 95 percent of the sugars they produce to the coral to use for energy," Weis said. "In return the algae gain nitrogen, a limiting nutrient in the ocean, by feeding off the waste from the coral. It's a finely developed symbiotic relationship."

What scientists are learning, however, is that this relationship is also based on a delicate communication process from the algae to the coral, telling it that the algae belong there, and that everything is fine. Otherwise the corals would treat the algae as a parasite or invader and attempt to kill it.

"Even though the coral depends on the algae for much of its food, it may be largely unaware of its presence," Weis said. "We now believe that this is what's happening when the water warms or something else stresses the coral – the communication from the algae to the coral breaks down, the all-is-well message doesn't get through, the algae essentially comes out of hiding and faces an immune response from the coral."

This internal communication process, Weis said, is not unlike some of the biological processes found in humans and other animals. One of the revelations in recent research, she said, is the enormous complexity of coral biology, and even its similarity to other life forms. A gene that controls skeletal development in humans, for instance, is the identical gene in corals that helps it develop its external skeleton – conserved in the different species over hundreds of millions of years since they parted from a common ancestor on their separate evolutionary paths.

There's still much to learn about this process, researchers said, and tremendous variation in it. For one thing, there are 1,000 species of coral and perhaps thousands of species of algae all mixing and matching in this symbiotic dance. And that variation, experts say, provides at least some hope that combinations will be found which can better adapt to changing conditions of ocean temperature, acidity or other threats.

The problems facing coral reefs are still huge, and increasing. They are being pressured by changes in ocean temperature, pollution, overfishing, sedimentation, acidification, oxidative stress and disease, and the synergistic effect of some of these problems may destroy reefs even when one cause by itself would not. Some estimates have suggested 20 percent of the world's coral reefs are already dead and an additional 24 percent are gravely threatened.

The predicted acidification of the oceans in the next century is expected to decrease coral calcification rates by 50 percent and promote the dissolving of coral skeletons, the researchers noted in their report.

"With some of the new findings about coral symbiosis and calcification, and how it works, coral biologists are now starting to think more outside the box," Weis said. "Maybe there's something we could do to help identify and protect coral species that can survive in different conditions. Perhaps we won't have to just stand by as the coral reefs of the world die and disappear."

Beavers return after 400-year gap

2009-05-29T01:05:00.000-07:00

A total of 11 beavers have been released into the wild in Argyll as part of a reintroduction programme.

Four more may join the Scottish Beaver Trial being run in Knapdale Forest.

The beavers have been brought to Scotland from Norway and their release marks a return to the UK after a 400-year absence.

The release will be studied to determine whether the trial should be extended and beavers reintroduced across Scotland.

Colin Galbraith, of Scottish Natural Heritage (SNH), has been an enthusiastic backer of the scheme.

He said: "I think this is a hugely exciting move and one in which we've got to take people with us.

"There's never been a reintroduction of a mammal back to the UK.

"We've done the red kite and the sea eagle - they've gone pretty well - people are now behind that.

"We've got to try to do this reintroduction of a mammal in a very scientific careful and monitored way."

But not everyone has been behind the scheme.

Alan Kettlewhite, a biologist with Argyll Fisheries Trust, said: "Potentially they can alter the habitats of fish, restricting access to spawning grounds.

"I think the concerns are based on studies in other countries where sometimes dam-building can prevent fish access to their spawning grounds, particularly in dry years where you don't get much rain in the autumn time."

But SNH's Colin Galbraith said he felt a duty towards the beavers.

"For me the argument is very simple. They were here - we killed them out. I think we've got the moral obligation to bring them back," he said.

Continuously tested

Project officer Jenny Holden said: "The main things people are concerned about are giardia and cryptosporidium.

"They are bacteria that can infect the guts of humans and make you feel really quite unwell - food-poisoning type bugs.

"The beavers that are released will have been tested continuously for six months and then throughout the five year trial to make sure they are clear of these bacteria.

"So if we find a few years down the line that the beavers are infected, they won't have brought it in, they will have caught it out in the environment here."

Darren Dobson is from the Carinbaan Hotel near the release site.

He is delighted at the prospect of beavers, and hopes they will prove to be a major tourist attraction.

He said: "Generally speaking it's all positive. I haven't met anyone myself who is negative to the idea.

"It's going to bring more tourists - and this is just one more thing to add to what this area's got."

Scottish Natural Heritage, (SNH), will monitor the relationship between beavers and woodland, water plants, river habitat, water levels, otters, dragonflies, damselflies and freshwater fish.

The beavers themselves will also be under close scrutiny, using tracking data.

SNH will co-ordinate the scientific monitoring work with a range of independent bodies, including Oxford University Wildlife Conservation Research Unit and the Argyll Fisheries Trust.

SNH is contributing £275,000 to the cost of monitoring the trial.

It is claimed the trial will be a major contribution to Scotland's Species Action Framework, which identifies 32 species, including European beaver, as the focus of new management action.

Virus Resistant 'Orange Bulldog' Pumpkins

2009-05-26T04:15:00.000-07:00

Move over 'Longface', 'Spooktacular' and 'Trickster' - there's a new face in the pumpkin patch. Welcome 'Orange Bulldog', a new variety of the familiar fall fruit that may soon be available to consumers and wholesale pumpkin growers. Researchers at the University of Georgia recently introduced the new, virus-resistant pumpkin, specifically developed for ornamental fall and Halloween displays.

Dr. Gerard Krewer from the Department of Horticulture at the University of Georgia's College of Agriculture and Environmental Sciences, collected pumpkin seeds in remote areas of Brazil in 1996. The Brazilian seeds were then planted in laboratories, hybridized, and ultimately used to develop 'Orange Bulldog'.

Dr. George Boyhan, Assistant Professor and Extension Horticulturist at the University of Georgia and lead author of the study published in the October 2007 issue of HortScience, explained that pumpkins have not been readily available in southern states because conventional pumpkins are highly susceptible to viruses and often die before they produce fruit.

The research team set out to develop a virus-resistant pumpkin with bright orange color and an open cavity that would be suitable for Halloween carving. According to Boyhan, 'Orange Bulldog' seeds "consistently produced fruit during fall production, whereas commercial pumpkin cultivars often succumb to severe virus infections before fruiting."

Although 'Orange Bulldog' is not yet available to growers or the public, Boyhan's team hopes that a commercial supplier will soon handle the seeds and make the new pumpkin available to pick-your-own pumpkin growers and consumers.

New Blackberry Fruit

2009-05-26T04:13:00.001-07:00

John R. Clark and James N. Moore of the Department of Horticulture at the University of Arkansas introduced 'Natchez' in the October 2008 issue of the American Society of Horticultural Science's journal HortScience. According to Clark, the new blackberry is a result of a cross of Ark. 2005 and Ark. 1857 made in 1998. The original plant was selected in 2001 from a seedling field at the University of Arkansas Fruit Research Station in Clarksville, and tested as selection Ark. 2241.

'Natchez' produces large fruit, near 9 grams on average in research trials. Fruit of 'Natchez' are elongated, somewhat blocky, and very attractive with an exceptional glossy, black finish.

'Natchez' exceeded postharvest performance of 'Arapaho' in most years. This is noteworthy, explain the researchers, because the comparison cultivars are considered to have exceptional shelf life. 'Natchez' is recommended for commercial shipping production, and is targeted as a replacement for the early season 'Arapaho'.

Outstanding characteristics of 'Natchez' include early fruit-ripening date, high fruit quality, consistent high yields, large fruit size, and excellent postharvest fruit-handling potential. Superior plant characteristics include thornless, erect to semierect canes and good vigor and health. 'Natchez' also shows good potential for home garden use.

'Natchez' is expected to perform well in areas where 'Apache', 'Arapaho', 'Ouachita', or 'Navaho' are adapted, including all areas of the South and into the Midwest, in addition to the West and Pacific Northwest.

An application for a U.S. plant patent has been filed for 'Natchez'.

'Delicious' New Grape Debuts

2009-05-26T04:12:00.000-07:00

Researchers at the University of Florida have introduced 'Delicious', a new muscadine grape cultivar. 'Delicious' ripens early, produces high yields, and is disease-resistant. The black fruit features exceptional taste and texture with an edible skin, making it well-suited for fresh fruit consumption and the potential for wine production. The name 'Delicious' was selected based on the comments of vineyard visitors who sampled the fruit.

According to Dr. Dennis J. Gray, who led the research study published in the February 2009 issue of HortScience, 'Delicious' (Vitis rotundifolia Michx.) originated from a cross between AA10-40, a self-fertile, bronze-fruited selection with medium-sized berries, and CD8-81, a self-fertile, black-fruited selection with larger berries. The researchers noted that black berry color of 'Delicious' likely originated from 'Southland' and the self-fertile trait came from 'Carlos', 'Southland', and/or 'Welder'. The original seedling was planted in 1993.

The berries of 'Delicious' are oval shaped and reddish, turning dark purple/black when ripe. Fruit ripening dates vary seasonally, but tend to occur in early August at Apopka, Florida, remarkably 2 to 3 weeks earlier than other muscadine cultivars evaluated. Early ripe fruit have a semicrunchy flesh and an edible skin. Fruit allowed to ripen further tend to have a softer flesh, become noticeably juicier, but retain an edible skin. The berries have a dry stem scar and harvest readily with mechanical shaking.

Although 'Delicious' is being released primarily as a fresh eating grape, it has some potential for wine. Based on preliminary trials, the flavor of the wine (2006 vintage) rated equal to those of 'Carlos' (a popular cultivar for wine) by a panel of 30 winemakers. The color is a medium to light red, generally lighter than many red muscadine wines.

Delicious' was publically released by the Cultivar Release Committee of the Florida Agricultural Experiment Station, an agricultural research program of the University of Florida's Institute of Food and Agricultural Sciences, in October 2007. Inquiries regarding the availability of 'Delicious' should be directed to Florida Foundation Seed Producers, Inc. P.O. Box 110200, Gainesville, FL 32611-0200.

http://www.ashs.org/

The 21st Century Tomato

2009-05-26T04:10:00.000-07:00

When tomatoes ripen in our gardens, we watch them turn gradually from hard, green globules to brightly colored, aromatic, and tasty fruits. This familiar and seemingly commonplace transformation masks a seething mass of components interacting in a well-regulated albeit highly complex manner.

For generations, agriculturalists and scientists have bred tomatoes for size, shape, texture, flavor, shelf-life, and nutrient composition, more or less, one trait at a time. With the advent of molecular biology, mutagenesis and genetic transformation could produce tomatoes that were more easily harvested or transported or turned into tomato paste. Frequently, however, optimizing for one trait led to deterioration in another. For example, improving flavor could have a negative effect on yield.

The revolution in genomics, with a wealth of data emerging from sequencing and simultaneous expression analysis of thousands of genes, has made it possible to study the numerous pathways and regulatory networks--systems--that operate to produce a desirable fruit. This systems approach in the new fields of metabolic and functional genomics is producing the tools, information, and biological materials needed for screening and breeding efforts in tomato and other members of the Solanaceae.

Dr. Fernando Carrari and his colleagues, Laura Kamenetzky, Ramon Asis, Luisa Bermudez, Ariel Bazzini, Sebastian Asurmendi, Marie-Anne Van Sluys, Jim Giovannoni, Alisdair Fernie, and Magdalena Rossi use a systems approach that integrates genomic, genetic, and biochemical tools to model the metabolic networks that interact in the process of tomato fruit development. Dr. Carrari, of the Instituto de Biotecnologia, (INTA), Argentina, will be presenting this work at a symposium on the Biology of Solanaceous Species at the annual meeting of the American Society of Plant Biologists in Mérida, Mexico (June 29, 9:10 AM).

Tomato (Solanum lycopersicum) is a member of the Solanaceae or nightshade family, which also includes potato, eggplant, tobacco, and chili peppers. The center of origin and diversity of tomato species is in the northern Andes, where endemic populations of wild tomato species still grow. These wild populations represent considerable genetic diversity, whereas cultivated tomatoes are genetically very narrow. The Tomato Genome Consortium is an international collaboration that is sequencing, mapping and analyzing the genomes of both wild and cultivated varieties. Carrari and his co-workers, as well as other scientists, have begun to make use of this wealth of sequence data in functional and metabolic analyses of tomato and other crops.

Plants produce an immense variety of chemical compounds for growth, metabolism, signaling, defense, and reproduction. These metabolites function in complex networks and pathways in which they regulate and are regulated by parallel networks of genes. It is not possible to realistically model these metabolic systems one compound or gene at a time.

Moreover, many, if not most traits in tomato, are not the result of one gene, but of many genes located together in chromosomal regions called quantitative trait loci (QTLs), because they produce a range of values in fruit or plant size or color, rather than just two extremes. Thus metabolites, enzymes, and genes must be analyzed simultaneously and in parallel in order to capture their dynamic relationships. To accomplish this, Carrari and his colleagues made use of the high genetic diversity of an ancestral tomato species, Solanum pennellii.

Through crosses, chromosomal segments of S. pennellii were introgressed into the genome of the cultivar Solanum lycopersicum var. Roma. Different lines of the cultivar were then created that differed only in the chromosomal segment received from the wild species. In this way, over 1200 metabolic QTLs or quantitative metabolic loci (QMLs) were identified and analyzed. Almost 900 of these QMLs were found to be associated with fruit metabolism.

The scientists then sampled a number of metabolites such as carbohydrates, pigments, and hormones, among others, throughout flower and fruit development. They also used microarrays to determine which genes were expressed at those same times. Pairwise comparisons and network analyses were then made to determine which of those genes and metabolites are associated in possible functional networks. These associations do not establish causality or regulatory direction, because they are only correlational. Expression of certain genes may regulate metabolite activity, but metabolites may also have a regulatory effect on gene expression.

To begin to define causal direction, Carrari and his colleagues perturbed these systems by treatment with external metabolites and followed the transmission of information from metabolite to gene. In continuing research, Carrari and co-workers are using these methods, as well as RNA interference and transgenesis to map QMLs and to identify and utilize candidate genes that function at network nodes.

These systems approaches make it possible to model the whole organism throughout its development. Moreover, an understanding of metabolic networks will make it possible to alter metabolic pathways to produce fruits with different secondary compounds that influence texture, taste, aroma, and nutrition, as well as to improve yield. Metabolite analysis also has possible applications in drug discovery, nutrient enhancement and biofuel production. One important goal is the use of ancestral genetic resources in place of simplistic genetic modification to avoid possible deleterious environmental effects as well as resistance by consumers to genetically modified food.

http://www.aspb.org/

Evolution Of Fruit Size In Tomato

2009-05-26T04:08:00.001-07:00

In general, domesticated food plants have larger fruits, heads of grain, tubers, etc, because this is one of the characteristics that early hunter-gatherers chose when foraging for food. In addition to size, tomatoes have been bred for shape, texture, flavor, shelf-life, and nutrient composition, but it has been difficult to study these traits in tomatoes, because many of them are the result of many genes acting together. These genes are often located in close proximity on chromosomal regions called loci, and regions with groups of genes that influence a particular trait are called quantitative trait loci (QTLs).

When a trait is influenced by one gene, it is much simpler to study, but quantitative traits, like skin and eye color in humans or fruit size in tomatoes, cannot be easily defined just by crossing different individuals. Now, with genome sequencing and genomics tools, chromosomal regions with QTLs can be mapped and cloned more easily than in the past. These genomic maps can also be compared across plant genomes to identify similar genes in other species. With this knowledge, breeders can improve tomato varieties as well as other less well known food plants in the family Solanaceae.

Dr. Steven D. Tanksley and his colleagues, Bin Cong and Luz S. Barrero, are studying QTLs that influence fruit size. Dr. Barrero, of the Corporación Colombiana de Investigación Agropecuaria (CORPOICA), Colombia, will be presenting this work at a symposium on the Biology of Solanaceous Species at the annual meeting of the American Society of Plant Biologists in Mérida, Mexico (June 29, 2008).

Tomato (Solanum lycopersicum) is a member of the Solanaceae or nightshade family, which also includes potato, eggplant, tobacco, and chili peppers. The center of origin and diversity of tomato and other solanaceous species is in the northern Andes, where endemic wild populations of these species still grow. Tanksley and his colleagues have been employing the data emerging from the International Tomato Genome Sequencing Project as well as the tools of structural genomics to clone and characterize the major gene and QTL responsible for extreme fruit size during tomato domestication--fas.

The first QTL, fw2.2, was the first ever cloned in plants and may have been the site of one of the earliest mutations in tomato that led to its selection by humans and subsequent domestication. The size of tomato fruit can vary up to 30% as a result of variation at this locus alone. Cloning and sequencing of this locus reveals that the wild type protein codes for a repressor of cell division. When the control sequence is mutated, the repressor protein is not expressed or only very little, leading to higher cell division during fruit development and, consequently, larger fruits.

However, fw2.2 and associated genes related to cell-cycle control and cell division are not solely responsible for extreme fruit size. Two other loci-- locule-number and fasciated (fas)-- influence fruit size indirectly by affecting the number of carpels, the female parts of the flower that will become seed chambers in the fruit. Most wild tomatoes have only 2-4 locules (ovary chambers) while domesticated varieties can have 8 or more, and it appears that increase in locule number can increase fruit size by 50%. The data indicate that, of the two loci, fas has the larger effect. Tanksley and his colleagues used positional cloning to isolate the fas locus.

Sequencing suggested that the fas gene encodes a protein (YABBY-like transcription factor) that controls transcription of DNA into RNA as the first step of gene expression. It also revealed that there were no changes in the protein coding region of the gene but rather the mutation consisted of an insertion in the first intron, which is a non-coding sequence embedded within the protein coding sequence.

Although introns are not part of a gene's protein code and are removed from the RNA sequence before translation into proteins, they are nevertheless structurally and functionally important, as demonstrated in this locus. The presence of an insertion in this intron reduces expression of the fas gene. The scientists looked at where and when the gene is expressed and found it dramatically reduced in developing flower buds in plants with high locule numbers.

Further comparisons of this locus across different tomato cultivars, including wild varieties, which turned out not to contain the mutation, suggests the mutation occurred relatively recently in tomato domestication and spread rapidly throughout modern tomatoes as a result of selection for extreme fruit size. Comparative genomics tools are being applied in both well-known and obscure solanaceous species. Conservation of genes and loci across a number of these species suggests that the knowledge gained from these efforts can also be applied in crop and yield improvement for other members of the Solanaceae.

http://www.aspb.org/

How Birds Spot The Cuckoo In The Nest

2009-05-25T08:56:00.000-07:00

It's not always easy spotting the cuckoo in the nest. But if you don't, you pay a high price raising someone else's chick. How hosts distinguish impostor eggs from their own has long puzzled scientists. The problem remained largely unsolved while looking at it through our own eyes. It was only when people started thinking from the birds' perspective that they began to understand how hosts recognise a cuckoo egg in the nest.

Marcel Honza from the Academy of Sciences of the Czech Republic explains that birds see UV wavelengths that are well outside our own visual range.

Knowing that many bird eggs reflect UV wavelengths, Honza wondered whether altering the reflected UV spectrum of an egg would affect a bird's ability to recognise it as foreign and reject it. Would a blackcap recognise and evict an impostor egg if the reflected UV spectrum were different from the wavelengths reflected by the bird's own clutch? Teaming up with Lenka Pola iková, Honza headed into a near-by forest to test blackcap responses to impostor eggs.

But instead of testing the birds' reactions to real cuckoo eggs, the team found abandoned blackcap eggs, introducing them as impostors to successful blackcap clutches. Having identified nests with well-established clutches, the team coated some impostor eggs in UV blocker, to alter their UV appearance, and others in Vaseline, which didn't alter the egg's UV reflectivity, before planting the impostors in their new nest. Then the team kept their fingers crossed, hoping that the nests weren't washed out by a heavy downpour or raided by a hungry predator, as they waited 5 days to see if the parents rejected the interlopers.

Of the 16 eggs coated in Vaseline, 11 of the impostors were accepted by the nesting parents, while five were rejected; most of the interloper blackcap eggs were visually indistinguishable from the nesting parents' own eggs and were accepted as belonging to the brood. However, it was a different matter for the birds sitting on UV-block-coated impostors. Seventeen brooding parents evicted the strange looking egg, pecking at the shell until they had made a large enough hole to stick their beak in and carry it away. Only 11 blackcaps accepted the interloper with its altered appearance.

The UV appearance of the eggs was very important in enabling the blackcaps to recognise the new eggs as impostors. The blackcaps rejected far more eggs when Pola iková and Honza covered them in UV block. By altering the eggs' UV reflectivity the team had made them stand out from the crowd.

Honza admits that he was surprised that the UV reflectivity had such a significant effect on the blackcap's ability to reject an impostor. Having found that an interloper's UV appearance is key to its acceptance in a clutch, Honza is keen to see whether cuckoos try to outsmart their victims by choosing clutches that closely match their own eggs' UV reflectivity

http://jeb.biologists.org/

Why Are Birds' Eggs Speckled?

2009-05-25T08:54:00.000-07:00

Birds' eggs are unique in their diverse pigmentation. This diversity is greatest amongst perching birds (order Passeriformes: 60% of all bird species), which include many familiar species including tits and warblers. Despite intense interest, the purpose, in most species, of these patterns was unknown.

Most passerines lay eggs speckled with reddish protoporphyrin spots forming a ring around the egg's blunt end, on an otherwise unpigmented shell. Evidence in a paper by Gosler, Higham & Reynolds soon to appear in Ecology Letters now suggests that rather than giving a visual signal, protoporphyrins strengthen the eggshell by compensating for reduced eggshell-thickness caused by calcium deficiency.

Pigment spots on great tit eggs specifically marked thinner areas of shell, with darker spots marking yet thinner shell than paler spots, and females nesting on low-calcium soils, laid thinner-shelled, more-spotted eggs than those on high-calcium soils nearby. Pigmentation may offer a way to assess eggshell quality.

http://eu.wiley.com/WileyCDA/Section/index.html

Salmonella Can Cause Poorer Eggshell Quality

2009-05-25T08:53:00.000-07:00

Veterinary medical officer Jean Guard Bouldin, at the ARS Southeast Poultry Research Laboratory in Athens, Ga., found an interesting phenomenon--not only was Salmonella present inside chicken eggs, but other bacteria were there also. Since these bacteria are usually seen in eggs that have been contaminated through cracks in the shell, Bouldin theorized that poor eggshell quality allowed the bacteria to enter the egg.

Salmonella enteritidis is hard to detect in chickens because there are no symptoms. This poses a significant problem, because S. enteritidis, found inside the egg, is an important cause of human food-borne illness.

Bouldin and Jeff Buhr, of the ARS Poultry Processing and Meat Quality Research Unit in Athens, Ga., conducted tests in which chickens were inoculated with S. enteritidis. Eggs were then tested for hardness by compressing them until a hairline crack formed. Eggs from Salmonella-infected hens cracked easier than those from noninfected hens. Other research has shown that some strains of S. enteritidis seem to target the hen's reproductive tract, which appears to result in an egg with a less resilient shell, according to Bouldin.

At low-dose infection, Bouldin found that S. enteritidis actually stimulated egg production, particularly in older hens. This increased production may have stretched the limited eggshell material--calcium--a bit too thin, literally.

Other diseases of chickens can also decrease shell quality, but usually they result in a decrease in production and illness in hens. Changes to eggshell quality over the lifespan of a laying hen are to be expected, and thus a hen's age could be an additional risk factor.

ARS is the USDA's chief scientific research agency.

Flies And Salmonella

2009-05-25T08:52:00.000-07:00

Agricultural Research Service (ARS) microbiologist Peter S. Holt and entomologist Christopher J. Geden found that the common housefly, Musca domestica, readily picks up bacteria from its surroundings. When the chickens eat the flies, the bacteria get inside the birds. Holt works in the Egg Safety and Quality Research Unit at the ARS Richard B. Russell Research Center in Athens, Ga., while Geden is at the ARS Center for Medical, Agricultural and Veterinary Entomology in Gainesville, Fla.

ARS is the U.S. Department of Agriculture's chief scientific research agency.

In three experiments, Holt placed chickens in individual, adjacent laying cages. Geden delivered fly pupae just 48 hours short of hatching as flies; this timing ensures the flies aren't exposed to any microbe prior to emergence. The fly pupae were placed in an open box in the bird room. Three days later, hens were orally infected with Salmonella.

The researchers detected the bacteria in and on 45 to 50 percent of the flies within the first 48 hours of the flies' hatching.

Next, uninfected hens were exposed to the newly infected flies. Just being around the flies didn't cause healthy birds to become infected, but eating infected flies did. This showed that simple physical contact may not be the primary method of transfer of Salmonella bacteria to different surfaces in a poultry house. But, according to the researchers, a hen's eating of contaminated flies does seem to be the primary mechanism of transmission of Salmonella from flies to birds.

According to Holt, this shows that flies in poultry houses are not only a nuisance, but also a threat to the safety of poultry products.

http://www.ars.usda.gov/main/main.htm

Salmonella In Garden Birds Responsive To Antibiotics

2009-05-25T08:50:00.001-07:00

Salmonella is increasingly resistant to antibiotics and can sometimes go undetected in animals, which increases the risk of the infection being spread to humans. The team tested the strains found in birds in the laboratory and found that antibiotics were able to kill off the bacteria.

Scientists believed that wild birds carried a variety of Salmonella strains and passed the infection on to livestock through their faeces. Scientists at Liverpool, however, have found that only two Salmonella strains are common in garden birds, neither of which is prevalent in livestock or humans.

Research showed that these strains were a fairly distinct population of bacteria and well adapted in garden birds. They were particularly common in finches - such as greenfinch, siskins and goldfinches - as well as house sparrows.

Dr Paul Wigley, from the National Centre for Zoonosis at the University of Liverpool, said: "Salmonella is a bacterium that causes intestinal infection in humans and can cause illness such as vomiting and diarrhoea - usually through contaminated food like meat or eggs. Symptoms in birds include weight loss, feather ruffling and lethargy. We have witnessed a number of deaths due to Salmonella infection in garden birds and so it was important that we investigated how the disease was being spread.

"We thought that wild birds were incubators for Salmonella but have now found that garden birds carry two strains of a group of Salmonella microorganisms, called Salmonella Typhimurium, itself only one of over 2,500 types of Salmonella. We screened Salmonella genes we knew to be involved in causing disease and found that they lacked a gene normally found in the human form of the infection.

"The work suggests that the infection will keep circulating in the same species, increasing the risk of further disease outbreaks. We now know that these Salmonella strains are not resistant to antibiotics but it would be inadvisable to use antibiotics in garden birds as this would inevitably lead to the development of antibiotic resistant bacteria within these populations. We also now need to explore other possible sources to understand the infection in livestock and humans."

The research, conducted as part of the Garden Bird Health Initiative led by the Institute of Zoology and in conjunction with the Health Protection Agency, is published in BMC Veterinary Research.

http://www.liv.ac.uk/

Salmonella's Sweet Tooth Predicts Its Downfall

2009-05-25T08:49:00.000-07:00

For the first time UK scientists have shown what the food poisoning bug Salmonella feeds on to survive as it causes infection: glucose.

Their discovery of Salmonella’s weakness for sugar could provide a new way to vaccinate against it. The discovery could also lead to vaccine strains to protect against other disease-causing bacteria, including superbugs.

“This is the first time that anyone has identified the nutrients that sustain Salmonella while it is infecting a host’s body,” says Dr Arthur Thompson from the Institute of Food Research.

The nutrition of bacteria during infection is an emerging science. This is one of the first major breakthroughs, achieved in collaboration with Dr. Gary Rowley at the University of East Anglia.

Salmonella food poisoning causes infection in around 20 million people worldwide each year and is responsible for about 200,000 human deaths. It also infects farm animals and attaches to salad vegetables.

During infection, Salmonella bacteria are engulfed by immune cells designed to kill them. But instead the bacteria multiply.

Salmonella must acquire nutrients to replicate. The scientists focused on glycolysis, the process by which sugars are broken down to create chemical energy. They constructed Salmonella mutants unable to transport glucose into the immune cells they occupy and unable to use glucose as food. These mutant strains lost their ability to replicate within immune cells, rendering them harmless

“Our experiments showed that glucose is the major sugar used by Salmonella during infection,” said Dr Thompson.

The mutant strains still stimulate the immune system, and the scientists have filed patents on them which could be used to develop vaccines to protect people and animals against poisoning by fully virulent salmonella.

Glycolysis occurs in most organisms including other bacteria that occupy host cells. Disrupting how the bacteria metabolise glucose could therefore be used to create vaccine strains for other pathogenic bacteria, including superbugs.

The harmless strains could also be used as vaccine vectors. For example, the flu gene could be expressed within the harmless Salmonella strain and safely delivered to the immune system.

The next stage of the research will be to test whether the mutants elicit a protective immune response in mice.

In Germany the nutrition of bacteria is the subject of a six-year priority programme of research to investigate why bacteria are able to multiply inside a host’s body to cause disease.

The IFR is an institute of the Biotechnology and Biological Sciences Research Council (BBSRC). This research was funded by a Core Strategic Grant from BBSRC.

http://www.ifr.ac.uk/

Neotropical Treefrog Can Choose To Lay Eggs In Water Or On Land

2009-05-25T04:07:00.000-07:00

When frogs reproduce, like all vertebrates, they either lay their eggs in water or on land -- with one exception, according to new research by a team of Boston University scientists who discovered a treefrog (Dendropsophus ebraccatus) in Panama that reproduces both ways. The neotropical frog makes a behavioral decision to lay egg masses aquatically in a pond or terrestrially on the overhanging plants above a pond, where the newly-hatched tadpoles simply fall into the water.

The dual reproductive capabilities enable this species of tree frogs to choose the best environment for egg development avoiding either aquatic predators or the hot tropical sunlight that dries out the eggs. In two shady forest ponds the mating frogs laid terrestrial egg masses, as expected from previous research. In a third pond in an old gravel quarry without a forest canopy, the vast majority -- 76 percent -- of the eggs were laid in water, supported by aquatic vegetation. The remaining 24 percent were on leaves above the pond, although the mortality rate of these eggs was high due to the heat and lack of shade.

To test if genetic differences made frogs lay eggs in water or on land, or if instead their different environments affected egg-laying choices, Touchon and Warkentin built miniature ponds in an open field and in the forest. When they placed pairs of mating treefrogs in the shaded ponds, the frogs laid eggs on leaves above the water. In unshaded ponds, however, frogs put most of their eggs in the water.

Although this frog is the first vertebrate discovered to show reproductive flexibility, Touchon and Warkentin emphasize that it is probably not alone. The way an animal reproduces has been viewed as fixed, since most aquatic eggs die on land, and terrestrial eggs drown in water. This little yellow treefrog shows us such inflexibility is not universal.

Thus, the evolutionary change from aquatic to terrestrial eggs -- which has happened many times -- may not be a dichotomous switch but instead represent movement along a continuum.

Touchon and Warkentin suggest that this treefrog "could represent an intermediate stage in the evolution of terrestrial reproduction, combining a retained ancestral capacity for aquatic development with a derived ability for terrestrial oviposition and development." This discovery opens new avenues of research into the evolution of reproduction on land. The treefrog's ability to vary where it lays its eggs might also help it cope with changes in its environment, improving its chances of surviving habitat clearing or climate change.

Australian Frog Species

2009-05-25T04:05:00.000-07:00

A groundbreaking new study into the mating and nesting practices of a common Australian frog has found they partner up to eight males sequentially – the highest recorded of any vertebrate.

Dr Phillip Byrne, from Monash University's School of Biological Sciences, has researched the frog species Bibron's toadlet (Pseudophryne bibronii) for six years and in this latest field trip, discovered a new behaviour undetected in a frog species until now.

"Our study revealed that females made the active decision to distribute their eggs between the nests of up to eight different males," Dr Byrne said.

Dr Byrne led the study, which involved Professor Scott Keogh from Australian National University, in an area at Jervis Bay National Park on the New South Wales south coast .

They worked overnight shifts from 6 pm to 6 am, seven days a week for over four months and kept track of almost 100 frogs.

Using DNA markers Dr Byrne found females that distributed their available eggs between the nests of more males, as opposed to leaving them in one nest, had elevated offspring survival, presumably by insuring against nest failure.

"Traditionally it was thought that males, but not females, should benefit from promiscuous behaviour because males generally invest less in reproduction. This level of promiscuity is a new record among vertebrates and certainly supports the old adage of not putting all your eggs in the one basket," Dr Byrne said.

"Our study advances our understanding of female promiscuity by being the first to show that promiscuous females can safeguard against choosing fathers that provide poor homes for their offspring.

"It is becoming increasingly apparent that females in many animal species choose to mate with multiple partners as a safeguard against choosing a genetically inferior sire, but insurance against a father who provides a lousy home is a novel and potentially widespread explanation for the evolution of female promiscuity," Dr Byrne said.

The Pseudophryne bibronii is brown to black in colour and at just 30mm in length is one of the smaller frog species in Australia. It can be found along the eastern states of Australia and lives in forests, heathlands and grasslands.

http://www.monash.edu.au/

Smallest Indian Land Vertebrate

2009-05-25T04:03:00.000-07:00

The India’s smallest land vertebrate, a 10-millimeter frog, has been discovered from the Western Ghats of Kerala by Delhi University Systematics Biologist, S D Biju and his colleagues.

Indian land vertebrates (all animals with backbone except fishes), comprises of 2,400 species including 218 frog species.

S D Biju and his colleagues discovered the tiny night frog living under leaf litter and among the roots of ferns in the humid rainforest of the Western Ghats of Kerala, a mountainous region in the western portion of India. Biju gave a new name for the frog, Nyctibatrachus minimus.

With adult males of barely 10 mm in length, Nyctibatrachus minimus is the smallest of all known Indian land vertebrates and compete with miniature frogs in other parts of the world, including Cuba, the Amazon and Borneo.

This frog can be found during nighttime (hence the common name of the genus- Nightfrog) and also can be heard (mating calls) from under the leaf litter during monsoon months, the ideal time for reproduction.

Biju has been working in the Western Ghats to find new species of frogs over the past several years, and his findings include the purple frog (Nasikabatrachus) and the first canopy frog (Philautus nerostagona) from India.

The discovery was published recently in the Journal Current Science.

http://www.du.ac.in/hindi/

New Golden Frog Discovered

2009-05-25T04:01:00.001-07:00

A new poisonous frog was recently discovered in a remote mountainous region in Colombia by a team of young scientists supported by the Conservation Leadership Programme (CLP). The new frog, which is almost two centimetres in length, was given the name the "golden frog of Supatá."

Originally, the young scientists thought the frog was similar to several other common species in the area. However, after scientific analysis of the frog's characteristics, and review of their findings by experts at Conservation International, it was determined that the golden frog of Supatá is unique and only found within a 20 hectare area in Colombia's Cundinamarca region. Colombia is one of the world's richest countries in amphibian diversity, with more than 583 species.

Unfortunately, since this frog is a recent discovery, and endemic to only the Cunidnamarca region, little is known about it. So far, scientists say that the golden frog of Supatá belongs to a group of "dart frogs" that are known to be highly venomous. In the coming months, the young scientists hope to have more information about the frog.

"The importance of this project is not just the discovery of the new frog," said Oswaldo Cortes, team leader and one of the winners of the 2007 Conservation Leadership Programme awards. "But, most importantly, what this new discovery shows is how little we still know about our planet, and the many species that haven't yet been discovered. This is why it is so important to work with local communities and educate them about the need for conservation."

Hundreds Of Rare Golden Frog Tadpoles

2009-05-25T04:00:00.000-07:00

Hundreds of golden frog tadpoles hatched at Hotel Campestre in El Valle earlier this month, product of the Golden Frog Project that started in 2001. The Project aims to serve as Noah's Ark until a solution to control a fungus is found.

Principal investigator Edgardo Griffith, STRI visiting scientist from Southern Illinois University and research assistant Heidi Ross were surprised at the event “We didn't expect that the conditions for reproduction were already there.”

The new facilities of Hotel Campestre include at least one 100 gal aquarium irrigated with tap water filtered with activated charcoal to insure purity. River stones with emerging algae, tropical plants and petri dishes containing tadpole food based on algae are also contained in the aquarium, providing a simple but effective ecosystem for the new golden frogs. These frogs are the survivors of many highland species in Panama, victims to a chitrid fungus Batrachochytrium dendrobatidis (Bd). Along with habitat loss, soils use change, and commercial overexploitation, Bd is responsible for the decimation of populations and extinction of many species of amphibians. No wild golden frogs are found in El Valle.

The new tadpoles are the offsprings of two resident couples of golden frogs of the Hotel. In normal conditions in the wild, without the fungus, maybe only 25% of the tadpoles would survive, but given the conditions provided by the project all 100% of tadpoles may reach adulthood.

The efforts to conserve the golden frog and many other species of amphibians is shared by ANAM, the Houston Zoo, the World Association for Zoos and Aquaria, World of Conservation, Zoo Atlanta, etc.

http://www.stri.org/

Colombian Frog Believed Extinct Found Alive

2009-05-25T03:58:00.000-07:00

Researchers exploring a Colombian mountain range found surviving members of a species of Harlequin frog believed extinct due to a killer fungus wiping out amphibian populations in Central and South America.

The discovery of what could be the last population of the painted frog (Atelopus ebenoides marinkellei) indicates the species has survived the fungus, providing hope that other species also might avoid elimination from the epidemic caused by a pathogenic fungus of unknown origin.

Professor Carlos Rocha and a team of researchers from the Pedagogical and Technological University of Boyacá - UTPC supported by Conservation International, the Darwin Initiative and the Fund for Environmental Action and Childhood made the discovery in early May in the deserts of Sarna and Toquilla in Boyacá in eastern Colombia.

The painted frog, which is found only in the deserts of Colombia’s highlands, was last seen in 1995 in the area of Siscunsi, in the same region as Boyacá. After 11 years without a sighting, scientists considered the species extinct because of a lethal skin fungus, known as chytridiomycosis, and other hazards threatening the survival of a third of all amphibian species around the world.

"The scientific importance of the finding must motivate us to adopt urgent measures toward saving the last of these amphibians, both in the wild and through captive breeding programs," said Fabio Arjona, executive director of Conservation International in Colombia. "That will require a lot of support from the local and international communities."

The painted frog is one of 110 species of a diverse group of neo-tropical amphibians that live mostly in Colombia. The country’s amphibian population is considered among the most diverse on Earth and key in the conservation efforts to protect amphibian species worldwide. So far, 42 of the 113 species of Atelopus found in the Tropical Andes Hotspot that includes parts of Colombia, Ecuador, Peru and Venezuela have experienced population declines of up to 50 percent.

Frogs provide innumerable ecosystem services by consuming insects and serving as indicators of overall environmental health of an ecosystem. The disappearance of amphibians could cause numerous consequences, including an increase in illnesses such as malaria due to the disappearance of amphibians that feed on mosquitoes carrying the disease. An extinction crisis among amphibians indicates drastic environmental changes caused by human impact such as deforestation and global warming.

The research was conducted as part of the Atelopus Initiative, a regional program that monitors the state of amphibian populations in the Tropical Andes Hotspot. CI will work with partners on extending Atelopus conservation initiatives into Peru and Bolivia under the Amphibian Conservation Action Plan created in 2005 as result of the 2004 Global Amphibian Assessment.

http://www.conservation.org/Pages/default.aspx

About 200 New Species Of Amphibians In Madagascar Discovered

2009-05-25T03:56:00.000-07:00

Between 129 and 221 new species of frogs have been identified in Madagascar, practically doubling the currently known amphibian fauna. The finding suggests that the number of amphibian species in Madagascar, one of the world’s biodiversity hotspots, has been significantly underestimated. According to the researchers, if these results are extrapolated at a global scale, the number of amphibian species worldwide could double.

Their study, conducted with participation of the Spanish Scientific Research Council (CSIC), is published in the journal Proceedings of the National Academy of Science.

As Professor David R. Vieites, CSIC researcher at the Spanish National Natural Sciences Museum in Madrid, states: “the diversity of species in Madagascar is far from being known and there is still a lot of scientific research to be done. Our data suggest that the number of new species of amphibians not only has been underestimated but it is spatially widespread, even in well studied areas. For example, two of the most visited and studied National parks, Ranomafana and Mantadía/Analamazaotra, harbour 31 and 10 new species respectively.”

Dr. Frank Glaw, curator of herpetology at the Zoologische Staatssammlung from Munich explains: ”During the past 15 years, we discovered and described over 100 new frog species from Madagascar, which led us to believe that our species inventory is almost complete. But as our new surveys show, there are many more species than we suspected.”

The paper suggests that the total biodiversity on the island could be much higher also in other groups, so the actual destruction of natural habitats may be affecting more species than previously thought. This is important for conservation planning, as the rate of destruction of rainforests in Madagascar has been one of the highest in the planet, with more than 80% of the historic surface of rainforest already lost.

“Although a lot of reserves and national parks have been created in Madagascar during the last decade, the actual situation of politic instability is allowing the cut of the forest within national parks, generating a lot of uncertainty about the future of the planned network of protected areas,” explains Vieites. Almost a quarter of the new species discovered have not been found yet in protected areas.

Biodiversity

The study proposes different criteria -- morphological, genetic and bioacoustic -- to assign the candidate species (the ones which have been identified as potential new species but not yet formerly described) to different categories. In Madagascar, the number of candidate species is higher than the number of described species in some genera.

“Using these criteria and the integration of different techniques under the principle of congruence could help to boost the inventory and the process of species description worldwide,” explains Vieites. Dr. Miguel Vences, professor at the Technical University of Braunschweig adds: "People think that we know which plant and animal species live on this planet. But the century of discoveries has only just begun – the majority of life forms on Earth is still awaiting scientific recognition."

Also participating in the study were researchers from the Technical University of Braunschweig, Museo regionale di Scienze Naturali from Torino, and the Hessisches Landesmuseum from Darmstadt.

Madagascar is the fourth largest island in the world and one of the most biodiverse areas globally, with a high degree of endemic species. “To get an idea of its biodiversity, while in the Iberian Peninsula are about 30 species of amphibians and in Germany about 20, in a single locality in Madagascar we can find ca. 100 species of frogs,” explains Vieites.

http://www.csic.es/index.do

Bees Are The New Silkworms

2009-05-23T00:12:00.000-07:00

Moths and butterflies, particularly silkworms, are well known producers of silk. And we all know spiders use it for their webs. But they are not the only invertebrates who make use of the strength and versatility of silk.

Dr Tara Sutherland and her group from CSIRO Entomology are looking at silks produced by other insects and the results of their recent work have been published in Molecular Biology and Evolution, in the paper Conservation of Essential Design Features in Coiled Coil Silks.

“Most people are unaware that bees and ants produce silk but they do and its molecular structure is very different to that of the large protein, sheet structure of moth and spider silk. The cocoon and nest silks we looked at consist of coiled coils - a protein structural arrangement where multiple helices wind around each other. This structure produces a light weight, very tough silk,” she says.

“We had already identified the honeybee silk genes,” says Dr Sutherland, “and now we have identified and sequenced the silk genes of bumblebees, bulldog ants and weaver ants, and compared these to honeybee silk genes. This let us identify the essential design elements for the assembly and function of coiled coil silks”.

“To do this, we identified and compared the coiled coil proteins from cocoon and nest silks from species which span the evolutionary tree of the social Hymenoptera (bees, ants and wasps),” she says.

Bees and ants produce high-performance silk and, although the silks in all these species are produced by the larvae and by the same glands, they use them differently.

Honeybee larvae produce silk to reinforce the wax cells in which they pupate, bulldog ant larvae spin solitary cocoons for protection during pupation, bumblebee larvae spin cocoons within wax hives (the cocoons are reused to store pollen and honey), and weaver ants use their larvae as ‘tools’ to fasten fresh plant leaves together to form large communal nests..

These groups of insects have evolved silks that are very tough and stable in comparison to the classical sheet silks and it is probable that the evolution of this remarkable material has underpinned the success of the social Hymenoptera.

Coiled coil silks are common in aculeate social insects i.e. those that have stings but not in aculeate parasitic wasps. These social insects are higher up the evolutionary tree and the coiled coil silks appear to have evolved about 155 million years ago.

The silk research is part of the joint CSIRO and Grains Research & Development Corporation (GRDC) Crop Biofactories Initiative (CBI).

http://www.csiro.au/

Spider Silks, The Ecological Materials Of Tomorrow?

2009-05-23T00:10:00.000-07:00

Spider silks could become the intelligent materials of the future, according to a review article published this month in the journal Microbial Cell Factories. The characteristics of spider silk could have applications in areas ranging from medicine to ballistics.

The distinctive toughness of spider silk could allow manufacturers to improve wound-closure systems and plasters, and to produce artificial ligaments and tendons for durable surgical implants. The silk could also be woven into strong textiles to make parachutes, body armour, ropes and fishing nets. A whole range of ecological materials could emerge from the industrial production of spider silk.

Thomas Scheibel, from the Department of Chemistry of the Technische Universität in München explains that there are currently over 34,000 described species of spider, each with a specific tool-kit of silks with different mechanical properties serving specific purposes.

For example, major ampullate silk, a very tough silk with a tensile strength comparable to Kevlar, is used for the primary dragline or scaffolding of the spider's web. Minor ampullate silk with its very low elasticity is used to reinforce the web, while the strong and stretchy flagelliform silk forms the capture spiral of the web.

Biotechnologists are currently analysing the properties of silk proteins and how they assemble into threads. Knowing exactly how silk fibers are formed and what mechanical properties result from different assembly processes could allow the manufacture of artificial spider silks with special characteristics such as great strength or biochemical activity.

"The future objective might not be to prepare identical copies of natural silk fibers, but rather to capture key structural and functional features in designs that could be useful for engineering applications" explains the author.

Spiders are territorial and cannibalistic and so impossible to farm. The only way to produce large quantities of silk is to engineer and insert silk genes into other cells or organisms. But this has been complicated by the nature of the genes, which include many repeated sequences and rely on a different codon reading system from ours. However, in recent studies parts of the genes were successfully inserted into the bacterium E. coli, mammal and insect cells, which in turn produced silk proteins.

"Using 'protein engineering' based on knowledge achieved from investigations of the natural silks, artificial proteins can be designed that allow bacterial synthesis at high yields" writes Scheibel in the article*.

Engineering new proteins would also allow the design of completely new types of silk fiber, which could assemble with biochemically or biologically active groups into new types of mesh. These 'intelligent' materials would then be able to carry out enzymatic reactions, chemical catalysis or electronic signal propagation, for example.

Before this can be achieved, the spinning of proteins into fibers has to be resolved. So far there have been a few attempts at spinning silk on silicon micro-spinnerets. The outcomes have been promising but are far from matching naturally produced silks. For the moment the fibers produced are too wide, with diameters ranging from 10 to 60mm, compared with diameters of 2.5 to 4.0mm in natural fibers.

http://www.biomedcentral.com/

Spider Silk: Could 'Webicillin' Beat Infections?

2009-05-23T00:08:00.000-07:00

Could a dose of webicillin beat that stubborn infection? Could a cobweb bandage help soldiers and accident victims with bleeding wounds? Is a wrapping of spider silk the key to preventing the body from rejecting implants?

A review of research on spider silk concludes that scientists have largely overlooked such possible medical applications of this extraordinary natural material, which is stronger than steel. In a report in the current (Sept. 13) issue of the ACS monthly journal Chemical Reviews, Randolph V. Lewis, of the University of Wyoming, describes other scientific research on spider silk during the last 15 years.

"Very few studies of biological testing of spider silk have been done in a rigorous manner," Lewis states.

"There is a large body of folklore concerning the antibiotic, wound-healing, and clot-inducing activity of spider silk. However, much of that lore has not been seriously tested."

The lore dates to the first century A.D. when spider webs were prized as wound dressings. They even found a place in Shakespeare's Midsummer Night's Dream: "I shall desire you of more acquaintance, good master cobweb," the character "Bottom" said. "If I cut my finger, I shall make bold of you."

The scanty scientific evidence is tantalizing, Lewis notes. He cites, for instance, animal studies concluding that spider silks do not induce an immune response -- which causes rejection of implants.

http://portal.acs.org/portal/acs/corg/content

Spider Blood Found In 20 Million Year Old Fossil

2009-05-23T00:06:00.000-07:00

A scientist from the University of Manchester has discovered the first identified droplets of spider blood in a piece of amber up to 20 million years old.

Two droplets of blood, technically known as haemolymph, have been preserved in the amber which also contains the spider -- Filistatidae -- a family commonly found in South America and the Caribbean.

The droplets are the first identified examples of spider blood ever found in an amber fossil. It is possible the blood could be used to extract DNA.

The fossil, which is 4cm long and 2cm wide, was discovered in the Dominican Republic and dates back to the Miocene period.

Palaeontologist Dr David Penney, of the School of Earth, Atmospheric and Environmental Sciences, has now used the blood droplets to trace how, when, and where the spider died all those years ago.

David, said: "It's amazing to think that a single piece of amber with a single spider in it can open up window into what was going on 20 million years ago.

"By analysing the position of the spider's body in relation to the droplets of blood in the amber we are able to determine how it died, which direction it was travelling in and even how fast it was moving."

In the latest issue of the journal Palaeontology (2005, vol. 48, part 5) David describes how the spider died. He believes the spider was climbing up a tree when it was struck head-on by a sudden strong flow of resin. The spider then became engulfed in the resin and died.

He argues that the shape and position of the blood droplets reveals which direction the spider was travelling in. It also reveals which of the spider's legs broke first.

David discovered the fossil in 2003 during a visit to the Museo del Ambar Dominicano in Puerto Plata, Dominican Republic. His research initially focused on the spider which he identified as an entirely new species of spider. On his return to the UK, further research revealed the droplets of blood and the information the fossil contained.

http://www.manchester.ac.uk/

Biggest Spider In The World

2009-05-23T00:01:00.000-07:00

The biggest spider ever to have walked the earth has been exposed as a 'fraud' by a University of Manchester scientist, who claims the creature is more crab than creepy crawly.

The University's resident arachnid expert Dr Paul Selden has arguably solved one of the greatest mysteries in palaeontology after becoming one of the first scientists to be allowed to examine a fossil of the creature since it was unearthed in Argentina more than twenty years ago.

Megarachne Servinei has appeared in the Guinness Book of Records as the 'World's Largest Spider' and plaster casts of the beast are exhibited in museums across the world, but Dr Selden is in no doubt that it is not a spider.

"As soon as I saw it I knew it wasn't a spider, but an ancient aquatic creature called a sea scorpion," says Dr Selden.

"It has large claws and two big compound eyes whereas spiders normally have eight small eyes. It also appears to have a very robust body or shell with ridges across its back which is not found in any spider known to man."

"This creature probably lived in a swamp and used its claws for sweeping up mud. If you had to compare it to something which is alive today you would probably choose a large crab or a lobster, not a spider."

Megarachne, which has a massive 50cm leg span, and measures more than a metre in length, was discovered in 1980 by Argentine palaeontologist Mario Hünicken who originally classified it as a spider. Mystery has always surrounded the accuracy of Hünicken's findings, but because the fossil was sealed in a bank vault following an ownership dispute, no one has ever been able to verify his work.

Dr Selden was one of the first experts to be allowed to see the fossil, and has since written a Paper with Hünicken, who accepts Dr Selden's new findings. In the Paper they find that Megarachne is not a spider, but a giant eurypterid (sea scorpion) and is closely related to a creature called Woodwardopterus, from the Carboniferous Period, found in Scotland with relatives in South Africa.

"Even though this isn't the biggest ever spider it is clearly an amazing beast. It is no less exciting, just a little less familiar. It means the biggest spider ever is now the living one - The Goliath Birdeater, Theraphosa leblondi," says Dr Selden.

http://www.manchester.ac.uk/

Biologists Names New Spider After Neil Young

2009-05-22T23:59:00.000-07:00

An East Carolina University biologist has brought his admiration of Neil Young to a whole new class. Or species, to be exact.

Jason Bond, an ECU professor of biology, has named a newly discovered trapdoor spider, Myrmekiaphila neilyoungi, after the legendary rock star.

“There are rather strict rules about how you name new species,” Bond said. “As long as these rules are followed you can give a new species just about any name you please. With regards to Neil Young, I really enjoy his music and have had a great appreciation of him as an activist for peace and justice.”

In 2007, Bond discovered the new spider species in Jefferson Co., Ala, and later co-wrote a paper with Norman I. Platnick, curator at the American Museum of Natural History in New York, on the genus.

Bond received $750,000 in grants from the National Science Foundation in 2005 and 2006 to classify the trapdoor spider species and contribute to the foundation’s Tree of Life project. He is both a spider systematist – someone who studies organisms and how they are classified – and taxonomist – someone who classifies new species.

Spiders in the trapdoor genus are distinguished on the basis of differences in genitalia, Bond said, from one species to the next. He confirmed through the spider’s DNA that the

Myrmekiaphila neilyoungi is an identifiable, separate species of spider within the trapdoor genus.

http://www.ecu.edu/

New Species Of Spiders Discovered In Papua New Guinea

2009-05-22T23:58:00.000-07:00

A University of British Columbia researcher has discovered dozens of species of jumping spiders that are new to science, giving scientists a peek into a section of the evolutionary tree previously thought to be sparse.

Jumping spiders are found in every part of the world except Antarctica. Capable of jumping 30 times their body length, some of the 5,000 documented species are common in households. They come in many shapes and sizes, some resembling ants or beetles.

"Instead of sitting at the centre of a web, jumping spiders found a new way to make a living by wandering around their habitat and pouncing – like cats – on their prey," says Wayne Maddison, a professor of zoology and botany and director of the Beaty Biodiversity Museum at UBC.

Two of the jumping spiders' eight eyes have evolved to be large with high-resolution vision to spot prey. Female jumping spiders also use this heightened visual sense to watch males, who show off their colourful bodies during courtship dances.

Maddison collected more than 500 individual spiders during an expedition with Conservation International (CI) last summer in the Kaijende Uplands, one of Papua New Guinea's largest undeveloped areas. Preliminary studies show as many as 130 species, including 30 to 50 never-before-identified species, may have been found on the trip.

Some of the species discovered are highly distinctive, occupying "lonely" branches on the evolutionary tree of jumping spiders. Further research on these new specimens will shed light on how jumping spiders evolved their unique features – a question that continues to puzzle scientists. "Our finding shows that the great age of discovery isn't over by far," says Maddison, who estimates there may be at least 5,000 more species of unidentified jumping spiders in the world.

The CI expedition also identified two new plants, three frogs and a gecko that are believed to be new to science. Maddison says the smaller animals — like insects and spiders — and plants may hold the secret to many of the world's unknown chemicals.

"Spider venom has evolved for millions of years to affect the neurological systems of the spider's insect prey, and each species of spider gives us another opportunity to find medically useful chemicals," says Maddison. "Jumping spiders with their remarkably miniaturized yet acute eyes could help us understand how to push the limits of vision. In addition to filling in the gaps in our planet's natural history, exploring spider biodiversity and evolution could potentially inform fields as diverse as medicine and robotics."

"More than anything else, it's an amazingly beautiful world and we're simply trying to reveal it," says Maddison, who will be sharing his experience on the expedition during an April 16 public lecture hosted by the Beaty Biodiversity Museum. "There is a whole lot of beauty in these small spiders if we look closely enough."

http://www.ubc.ca/

Birds Have A Good Sense Of Smell

2009-05-22T04:51:00.000-07:00

Sight and hearing are the most important senses for birds - this is at least the received wisdom. By studying bird DNA, however, researchers at the Max Planck Institute for Ornithology, along with a colleague at the Cawthron Institute in New Zealand, have now provided genetic evidence that many bird species have a well-developed sense of smell .

The sense of smell might indeed be as important to birds as it is to fish or even mammals. This is the main conclusion of a study by Silke Steiger (Max Planck Institute for Ornithology) and her colleagues. The sense of smell in birds was, until quite recently, thought to be poorly developed.

Recent behavioural studies have shown that some bird species use their sense of smell to navigate, forage or even to distinguish individuals. Silke Steiger and her colleagues chose a genetic approach for their study. Their research focused on the olfactory receptor (OR) genes, which are expressed in sensory neurons within the olfactory epithelium, and constitute the molecular basis of the sense of smell. The total number of OR genes in a genome may reflect how many different scents an animal can detect or distinguish. In birds such genetic studies were previously restricted to the chicken, hitherto the only bird for which the full genomic sequence is known.

In addition to the chicken, the researchers compared the OR genes of eight distantly related bird species. They estimated the total number of OR genes in each species’ genome using a statistical technique adapted from ecological studies where it is used to estimate species diversity. They found considerable differences in OR gene number between the nine bird species. The brown kiwi from New Zealand, for example, has about six times more OR genes than the blue tit or canary.

"When we looked up the relative sizes of the olfactory bulb in the brain, we also noticed similar big differences between species", said Steiger. "It is likely that the number of OR genes correlates with the number of different smells that can be perceived. As the olfactory bulb is responsible for processing olfactory information, we were not too surprised to see that the number of genes is linked to the size of the olfactory bulb." Wide variation in numbers of OR genes, and sizes of olfactory bulbs, has also been found amongst mammals.

The implication of this finding is that different ecological niches may have shaped the OR gene repertoire sizes in birds, as has been suggested for mammals. The high number of OR genes in the kiwi could be explained by this bird’s unusual ecological niche. Unique among birds, the nostrils of the night-active kiwi are at the tip of the bill. When kiwis probe the forest floor in search of food, they are guided by smell rather than sight. Indeed the snuffling, nocturnal kiwis are sometimes considered to be New Zealand’s equivalent of a hedgehog!

Besides the total number of OR genes, the researchers estimated which proportion of these genes are functional. This was done because, in mammals, a reduced dependence on the sense of smell is associated with OR genes gradually accumulating mutations and so becoming non-functional. For example, in humans, which have a poor sense of smell compared with most other mammals, only about 40% of all OR genes may be functional. However, in the bird species studied by Steiger et al., the large majority of the OR genes were functional, again indicating that the sense of smell is much more important in birds than previously thought.

From the analysis of the chicken genome three years ago a new class of OR genes was found. Now Silke Steiger and her colleagues have shown that this class of genes seems to be a shared feature of all birds, while such OR genes are not found in other vertebrates such as fish, mammals or reptiles. The specific function of this class of bird-specific OR genes remains unknown.

http://www.mpg.de/

Bird Sex Is Something Else

2009-05-22T04:50:00.000-07:00

We've all heard about the birds and the bees. But apparently when it comes to birds, they have an unusual take on his and hers -- and the difference is genetic. Species with differentiated sex chromosomes (X and Y in humans, for example) get around the fact that males and females get different-sized portions of sex chromosome genes with a balancing act geneticists call dosage compensation. But research published today in the Journal of Biology shows that birds are extraordinary, because some bird genomes can live with an apparent overdose of sex-related genes.

US researchers Itoh, Melamed et al. working in Arthur Arnold's University of California, Los Angeles laboratory used RNA microarray analysis for their dosage compensation study. The team sampled chickens and zebra finches, and compared the results with data from humans and mice. In several types of finch and embryonic chicken brain tissue, Z chromosome genes were expressed up to 40% higher in ZZ males than ZW females. This contrasts with findings from the mammal samples, where dosage compensation meant that the male: female ratio of X-linked genes is similar to that of autosomal genes.

In mammals, mismatched doses of X genes between males and females threaten to upset the gene network in one or both sexes. Fruit flies (Drosophila), roundworms (C. elegans) and humans each work around this dosage problem using different molecular pathways. By contrast, for birds it appears that most genes on the Z chromosome are not fully dosage-compensated, at least at the transcriptional level.

The study challenges current thinking about the role and mechanisms of dosage compensation in species with heteromorphic sex chromosomes. "Unlike mammals, birds have an ineffective dosage compensation," says Arnold. "The finding is surprising because dosage compensation was previously thought to be critical for survival. Birds, however, seem to be doing just fine without sexual equality of Z gene expression".

http://www.biomedcentral.com/

Are Males The Weaker Sex?

2009-05-22T04:48:00.000-07:00

Male seagulls may be more vulnerable to their environment during embryonic development than females, according to Maria Bogdanova and Ruedi Nager from the University of Glasgow in the UK. Until now, the sex differences in developmental rate and susceptibility to unfavorable conditions during the embryonic stage in birds have received little attention.

In many birds, siblings hatch at different times, resulting in age hierarchies within broods, with younger chicks often suffering reduced competitive ability and poorer survival compared to older siblings. During the last phase of incubation, birds’ auditory system is developed and embryos communicate with each other by auditory stimuli. These vocalizations may act as a cue for later-developing embryos about forthcoming competition, and there is evidence that they can respond to these cues by accelerating their hatching time, to reduce their age disadvantage. However, it is unclear whether this flexibility in developmental rates is sex-specific.

Bogdanova and Nager experimentally manipulated the social environment of herring gull embryos and tested whether sibling contact during the embryonic stage affects the developmental rate of males and females differently, and whether this has consequences for their post-hatching performance. The last-laid eggs – female gulls commonly lay three eggs - were incubated either alone with no information about the presence of older siblings (experimental group), or in contact with other eggs which provided information about the presence of more advanced embryos (control group, replicating natural conditions). Post-hatching, the chicks were reared either with nest mates or alone.

The researchers found a sex-specific effect of social environment on hatching duration and fledging* condition. When incubated in isolation, males hatched faster than females but both sexes fledged in similar, relatively good, condition. In contrast, when incubated with normal between-embryo contact, males were unable to hatch as fast and fledged in significantly poorer condition than females, regardless of whether they were reared singly or in a brood.

The authors conclude that their findings confirm that there are differences in the way male and female herring gull chicks respond to the challenges of hatching at different times. It would appear that females have the upper hand.

*to fledge: to develop wing feathers that are large enough to allow the young bird to fly.

http://www.springer.com/?SGWID=5-102-0-0-0

Female Birds Boost Up Their Eggs When Hearing Sexy Song

2009-05-22T04:45:00.001-07:00

In a new study published in the latest issue of Ethology researchers show that female songbirds can alter the size of eggs and possibly the sex of their chicks according to how they perceive their mate's quality.

The researchers played back attractive ("sexy") songs and less attractive control songs of male canaries to female domesticated canaries. When the females started egg-laying they varied the size of their eggs in the nest according to the attractiveness of the male's song. That is, the more attractive the song, the larger the eggs.

However it is remarkable that while larger eggs were more likely to contain male offspring in natural environments, in the experiment there was no difference in brood sex ratio between the different songs played to the females, which suggests different levels of female control. Male birdsong has long been known to attract females and influence mate choice decisions and even induce an alteration in the offspring's sex ratio. This study by Leitner et al. now shows experimentally that hearing attractive song also has a selective impact on female physiology.

45 female domesticated canaries participated in this study that was a collaboration of Royal Holloway, University of London and the Max Planck Institute for Ornithology in Seewiesen and Radolfzell in Germany. The birds were kept in large aviaries where their daily behaviour was monitored in a colony before they were tested in the song experiments. The females showed a remarkable consistency in their behavioural and reproductive performance and the song stimuli alone were sufficient to elicit a profound physiological change.

This study further highlights the importance of behavioural stimuli for reproductive physiology. Bathroom Pavarottis beware.

http://eu.wiley.com/WileyCDA/Section/index.html

Birds Communicate Reproductive Success In Song

2009-05-22T04:43:00.000-07:00

Some migratory songbirds figure out the best place to live by eavesdropping on the singing of others that successfully have had baby birds -- a communication and behavioral trait so strong that researchers playing recorded songs induced them to nest in places they otherwise would have avoided.

This suggests that songbirds have more complex communication abilities than had previously been understood, researchers say, and that these "social cues" can be as or more important than the physical environment of a site.

The discovery was just published in Proceedings of the Royal Society B by scientists from Oregon State University, along with collaborators from Wellesley College, Queen's University and Trent University in Ontario, Canada.

"Finding the right habitat in which to breed is a matter of life and death for most birds," said Matthew Betts, an OSU assistant professor of forest science and expert on avian ecology. "They don't live a long time and they need to get it right the first time."

"The common wisdom is that these birds select sites solely on vegetation structure," Betts said. "If a bird selects a site for its nest that doesn't have the appropriate cover and food supply, it most likely won't be able to successfully breed. But now we know that young birds can listen to the songs of more experienced and successful birds and use this to help decide where they will nest the next year."

The scientists discovered this in experimental studies at 54 research sites with the black-throated blue warbler in the White Mountains of New Hampshire. During the fall when some of these birds had successfully mated and were singing to their young -- probably to teach the young ones how to sing -- the researchers played recordings of their song in other places that were, in fact, lousy bird habitat. Other black-throated blue warblers flying overhead heard these songs and decided it must be a good place to live, all visual evidence to the contrary, and returned to these exact sites the next spring to nest.

Male birds were four times more likely to follow the cues provided by song than by their own observations of the physical environment, the study showed. And even though the male had made a poor choice, the females -- too trusting for their own good - followed them there.

"We had a lot of birds come to settle in inappropriate habitat, just because they had heard our recorded bird songs there the previous year," Betts said. "We were actually pretty surprised that the effect of this communication was so strong."

The study was done with a single species of songbird, Betts said, but its findings are probably relevant to at least some other songbirds and perhaps other animal species as well. Much is not yet understood about the nature and importance of animal communication, but studies such as this make it clear that animals are, in fact, talking to each other in a social manner with information of considerable significance.

In the natural world, Betts said, there's a cost to making noise of any type -- among other things, it can alert potential predators to your presence. So "it makes sense that if there's a risk to vocal communication, there must also be some important benefits."

It's been understood for some time, he said, that birds make various noises and songs for specific reasons, such as to defend their territory or attract mates -- a "soft song" is often used in the presence of the female. This study takes the significance of that communication to a higher level, implying that what a bird hears may be more important than what they actually see or experience.

This ability, he said, may also be highly useful in the advent of climate change or other rapidly changing habitat conditions. It's a valuable shortcut. If birds can simply listen to vocal cues and make rapid decisions about something as important as future nesting habitat, Betts said, they may be able to respond more quickly and appropriately to degraded environmental conditions without having to experience them personally.

"If a bird can fly over a broad area and just by listening to songs identify 10 good places to nest, there's a real value to that," Betts said.

"Most migratory songbirds are very territorial and still might fight for those places next year, but one of them might be vacant, just from some bird that died over the winter," he said. "With little energy the songbird has found a successful place to rear its young, just by listening to other birds sing about their parental success."

http://oregonstate.edu/

Bird Songs Change With The Landscape

2009-05-22T04:41:00.000-07:00

As vegetation reclaimed formerly cleared land in California, Oregon and Washington over the last 35 years, male white-crowned sparrows have lowered their pitch and slowed down their singing so that their love songs would carry better through heavier foliage.

"This is the first time that anyone has shown that bird songs can shift with rapid changes in habitat," says biologist Elizabeth Derryberry who made the finding as part of her dissertation research at Duke University.

She compared recordings of individual birds in 15 different areas with some nearly forgotten recordings made at the same spots in the 1970s by a California Academy of Sciences researcher, and found that the musical pitch and speed of the trill portion of the sparrows' short songs had dropped considerably. "I was really surprised to find that songs had changed in a similar way in so many different populations."

She then used archival aerial photography to see how the foliage had changed in a subset of those spots, and found that the one population whose song hadn't slowed down lived in an area where the foliage hadn't changed either.

The physics is clear, but the biology is a little less certain. A lower, slower song suffers less reverberation in denser foliage and will be heard more accurately. In turn, that means it is more likely to be copied by young males who are choosing which song they will learn. Over generations, that should cause the song to slow down and drop in pitch as the foliage changes.

In the short term however, Derryberry doesn't know whether the clearer song wins better territories or mates, although she does know that these changes in song do affect both male and female behavior.

The results add to a growing body of evidence that the acoustic and visual communications of animals change with their habitat. "Given how much the world's habitats are changing, this is sort of an unexpected but useful factor to monitor," Derryberry said. She's now testing the broader effects of ecology on song evolution in birds across areas of South America where habitat may be changing due to deforestation and global warming.

Derryberry, who earlier discovered that female white-crowned sparrows preferred the slower new songs to the chirpy old ones, is now a researcher at Louisiana State University.

http://www.duke.edu/

Transmitting Prion Diseases In Milk

2009-05-21T00:53:00.000-07:00

Scrapie can be transmitted to lambs through milk, according to new research. The study provides important information on the transmission of this prion-associated disease and the control of scrapie in affected flocks. Scrapie is a fatal neurodegenerative disease of sheep and goats. Clinical signs include itchiness, head tremor, wool loss and skin lesions as well as changes in behaviour and gait.
Timm Konold and colleagues from the Veterinary Laboratories Agency in Weybridge, UK, investigated the transmission of scrapie by feeding milk from scrapie-affected ewes to lambs that are genetically susceptible to contracting scrapie. The researchers were looking for the presence of the prion protein, PrPd, which is associated with the disease.

Eighteen lambs were fed milk from scrapie-affected ewes. Three of these lambs were culled and two were found to have PrPd in intestinal tissues. The prion protein was also detected in lymphoid tissue of the gut of the surviving lambs and in some control lambs mixed with the scrapie milk recipients after weaning.

This suggested that scrapie milk recipients were able to shed the infectious agent and infect other lambs. There was no sign of PrPd in tissue samples from a control group of 10 lambs(one culled and the rest alive), which were housed in the same building but fed milk from healthy ewes. The research will continue, to see whether the lambs with PrPd develop the disease as they get older.

This work raises the possibility that other prion diseases could be transmitted in sheep via milk although it should have no direct implications for human health. Scrapie has been found in sheep and has not been shown to be transmissible to humans. BSE has not been found naturally in sheep and occurrence in sheep in the UK is considered to be unlikely. This research adds to our understanding of the transmission of prion diseases in sheep and would help to inform measures needed to protect human health if BSE were ever to be found in sheep.

http://www.biomedcentral.com/bmcvetres/

Oldest Sheep Contribute Most To Population Growth

2009-05-21T00:51:00.000-07:00

Populations of wild animals face the challenge of surviving in a changing climate. Researchers at Imperial College London and Université Claude Bernard Lyon have shown how a sheep population on a remote island off the west coast of Scotland responds to two consequences of climate change: altered food availability and the unpredictability of winter storms.

Dr. Thomas Ezard, lead author of the study, revealed, "When times are good and food is plentiful, lambs contribute almost twice as much to changes in population size than when times are hard. On the flip side, the oldest sheep contribute most to population growth when conditions are harsh."

The work suggests that the dynamics of populations are influenced not only by the weather but also by the ability of individuals to respond to it.

New mathematical breakthroughs have made it possible to show how environmental change affects populations, like these sheep.

The key is appreciating

how weather affects individual sheep and
how the weather changes from one year to the next.
If consecutive years have similar weather, the dynamics of the population will be very different than if conditions are unrelated from one year to the next.

Professor Tim Coulson concluded, "A thorough understanding of the likely effects of climate change on the ecology of wild populations requires linking populations to their environment. This demands application of innovative mathematical methods, as used here."

http://www.journals.uchicago.edu/

How Animals Will Respond To Climate Change

2009-05-21T00:49:00.000-07:00

Most predictions of how animals will move in changing climates rely on statistically relating an animal's current location to environmental conditions. This approach ignores potentially important aspects of an animal's biology including size, physiology, and behavior.
Lauren Buckley, an ecologist at the Santa Fe Institute, has developed a bottom-up approach that predicts distributions directly from an animal's traits and environmental conditions by modeling the energy use of individuals and populations. Research forthcoming in The American Naturalist applies the model to five populations of a widespread North American lizard, Sceloporus undulatus, to examine whether geographic variation in traits influences range predictions.

Buckley finds that lizards from the five populations are suited to live in different areas and are predicted to respond differently to a climate warming of 3°C, contrasting the predictions of statistical models.

While all populations are predicted to shift northward in response to climate warming, the extent of the predicted northward shift depends on the lizard's traits.

The research suggests that mechanistic modeling approaches that consider an animal's biology will be essential to realistic predictions of how animals will respond to climate change. The research points to the importance of biological factors such as adaptation of physiology, interactions with other organisms, and movement limitations.

"Additional biologically-based approaches to predicting how animals will respond to climate change are urgently needed," noted Buckley. "Without such approaches, we will likely be surprised by how the peculiarities of an animal's biology influence its range shifts."

This research was published in the January issue of the American Naturalist.

http://www.journals.uchicago.edu/

Why Do Cold Animals Make Bigger Babies?

2009-05-21T00:47:00.000-07:00

Reproduction involves a critical decision: Should an organism invest energy in a few large offspring or many small ones?
In a new study from The American Naturalist, Michael Angilletta (Indiana State University), Chris Oufiero (University of California, Riverside), and Adam Leaché (University of California, Berkeley) used a new statistical approach that can test multiple theories at the same time, an approach they hope will shed light on many evolutionary problems.

They used data from many populations of Eastern Fence Lizards (Sceloporus undulatus), which revealed that the lizards in colder environments produce larger offspring than lizards in warmer environments.

So why do animals in colder climates produce larger offspring? One theory suggests the larger size of offspring counteracts their slow growth in the cold. Yet another theory suggests large offspring are not directly linked to temperature at all. Instead, large offspring just happen to be produced by large mothers, who grow large because they require more energy to reproduce in the cold.

When they tested the theories simultaneously with their new approach, the team concluded that temperature's effect on reproduction is a byproduct of its effect on adult size. "This result could have widespread significance," says Angilletta. "Temperature determines the adult size of virtually all organisms. For many of these organisms, we expect temperature to also leave an imprint on reproduction."

Founded in 1867, The American Naturalist is one of the world's most renowned, peer-reviewed publications in ecology, evolution, and population and integrative biology research. AN emphasizes sophisticated methodologies and innovative theoretical syntheses--all in an effort to advance the knowledge of organic evolution and other broad biological principles.

http://www.journals.uchicago.edu/

DNA Isn’t Everything

2009-05-21T00:46:00.000-07:00

Research into epigenetics has shown that environmental factors affect characteristics of organisms. These changes are sometimes passed on to the offspring. ETH professor Renato Paro does not believe that this opposes Darwin’s theory of evolution.
A certain laboratory strain of the fruit fly Drosophila melanogaster has white eyes. If the surrounding temperature of the embryos, which are normally nurtured at 25 degrees Celsius, is briefly raised to 37 degrees Celsius, the flies later hatch with red eyes. If these flies are again crossed, the following generations are partly red-eyed – without further temperature treatment – even though only white-eyed flies are expected according to the rules of genetics.

Environment affects inheritance

Researchers in a group led by Renato Paro, professor for Biosystems at the Department of Biosystems Science and Engineering (D-BSSE), crossed the flies for six generations. In this experiment, they were able to prove that the temperature treatment changes the eye colour of this specific strain of fly, and that the treated individual flies pass on the change to their offspring over several generations. However, the DNA sequence for the gene responsible for eye colour was proven to remain the same for white-eyed parents and red-eyed offspring.

The concept of epigenetics offers an explanation for this result. Epigenetics examines the inheritance of characteristics that are not set out in the DNA sequence. For Paro, epigenetic mechanisms form an additional, paramount level of information to the genetic information of DNA.

Such phenomena could only be examined in a descriptive manner in the past. Today, it has been scientifically proven, which molecular structures are involved: important factors are the histones, a kind of packaging material for the DNA, in order to store DNA in an ordered and space-saving way. It is now clear that these proteins have additional roles to play. Depending on the chemical group they carry, if they are acetylated or methylated, they permanently activate or deactivate genes. New methods now allow researchers to sometimes directly show which genes have been activated or deactivated by the histones.

Cells have a memory

Epigenetic marks, such as the modifications of the histones, are also important for the specialisation of the body’s cells. They are preserved during cell division and are passed on to the daughter cells. If skin cells divide, more skin cells are created; liver cells form liver cells. In both cell types, all genes are deactivated except the ones needed by a skin or liver cell to be a skin or liver cell, and to function appropriately. The genetic information of the DNA is passed on along with the relevant epigenetic information for the respective cell type.

Paro’s group is researching this cell memory. It is still unclear how the epigenetic markers are passed on to the daughter cells. During cell division, the DNA is doubled, which requires the histones – as the current picture suggests – to break apart. The question is therefore how cellular memory encoded by epigenetic mechanisms survives cell division.

Emerging area of research

A similar question remains for the inheritance of the epigenetic characteristics from parents to offspring. They now know that when the gametes are formed, certain epigenetic markers remain and are passed on to the offspring. The questions, which are currently being researched, are how much and which part of the epigenetic information is preserved and subsequently inherited.

The research is also looking at the influence of various substances from the environment on the epigenetic constitution of organisms, including humans. Diet and epigenetics appear to be closely linked. The most well known example is that of the Agouti mice: they are yellow, fat and are prone to diabetes and cancer. If Agouti females are fed with a cocktail of vitamin B12, folic acid and cholin, directly prior to and during pregnancy, they give birth to mainly brown, slim and healthy offspring. They in turn mainly have offspring similar to themselves.

Contradiction to Darwin?

Environmental factors, which change the characteristics of an individual and are then passed on to its offspring, do not really fit into Darwin’s theory of evolution. According to his theory, evolution is the result of the population and not the single individual. “Passing on the gained characteristics fits more to Lamarck’s theory of evolution”, says Paro.

However, he still does not believe Darwin’s theory of evolution is put into question by the evidence of epigenetics research. “Darwin was 100 percent right”, Paro emphasises. For him, epigenetics complement Darwin’s theory. In his view, new characteristics are generated and passed on via epigenetics, subject to the same mechanisms of evolution as those with a purely genetic origin.
http://www.ethlife.ethz.ch/index

100 Reasons To Change The Way We Think About Genetics

2009-05-21T00:44:00.000-07:00

For years, genes have been considered the one and only way biological traits could be passed down through generations of organisms.

Not anymore.

Increasingly, biologists are finding that non-genetic variation acquired during the life of an organism can sometimes be passed on to offspring—a phenomenon known as epigenetic inheritance. An article forthcoming in the July issue of The Quarterly Review of Biology lists over 100 well-documented cases of epigenetic inheritance between generations of organisms, and suggests that non-DNA inheritance happens much more often than scientists previously thought.

Biologists have suspected for years that some kind of epigenetic inheritance occurs at the cellular level. The different kinds of cells in our bodies provide an example. Skin cells and brain cells have different forms and functions, despite having exactly the same DNA. There must be mechanisms—other than DNA—that make sure skin cells stay skin cells when they divide.

Only recently, however, have researchers begun to find molecular evidence of non-DNA inheritance between organisms as well as between cells. The main question now is: How often does it happen?

"The analysis of these data shows that epigenetic inheritance is ubiquitous …," write Eva Jablonka and Gal Raz, both of Tel-Aviv University in Israel. Their article outlines inherited epigenetic variation in bacteria, protists, fungi, plants, and animals.

These findings "represent the tip of a very large iceberg," the authors say.

For example, Jablonka and Raz cite a study finding that when fruit flies are exposed to certain chemicals, at least 13 generations of their descendants are born with bristly outgrowths on their eyes. Another study found that exposing a pregnant rat to a chemical that alters reproductive hormones leads to generations of sick offspring. Yet another study shows higher rates of heart disease and diabetes in the children and grandchildren of people who were malnourished in adolescence.

In these cases, as well as the rest of the cases Jablonka and Raz cite, the source of the variation in subsequent generations was not DNA. Rather, the new traits were carried on through epigenetic means.

There are four known mechanisms for epigenetic inheritance. According to Jablonka and Raz, the best understood of these is "DNA methylation." Methyls, small chemical groups within cells, latch on to certain areas along the DNA strand. The methyls serve as a kind of switch that renders genes active or inactive.

By turning genes on and off, methyls can have a profound impact on the form and function of cells and organisms, without changing the underlying DNA. If the normal pattern of methyls is altered—by a chemical agent, for example—that new pattern can be passed to future generations.

The result, as in the case of the pregnant rats, can be dramatic and stick around for generations, despite the fact that underlying DNA remains unchanged.

Lamarck revisited

New evidence for epigenetic inheritance has profound implications for the study of evolution, Jablonka and Raz say.

"Incorporating epigenetic inheritance into evolutionary theory extends the scope of evolutionary thinking and leads to notions of heredity and evolution that incorporate development," they write.

This is a vindication of sorts for 18th century naturalist Jean Baptiste Lamarck. Lamarck, whose writings on evolution predated Charles Darwin's, believed that evolution was driven in part by the inheritance of acquired traits. His classic example was the giraffe. Giraffe ancestors, Lamarck surmised, reached with their necks to munch leaves high in trees. The reaching caused their necks to become slightly longer—a trait that was passed on to descendants. Generation after generation inherited slightly longer necks, and the result is what we see in giraffes today.

With the advent of Mendelian genetics and the later discovery of DNA, Lamarck's ideas fell out of favor entirely. Research on epigenetics, while yet to uncover anything as dramatic as Lamarck's giraffes, does suggest that acquired traits can be heritable, and that Lamarck was not so wrong after all.

http://www.journals.uchicago.edu/

Rare White Killer Whale Spotted In Alaskan Waters

2009-05-20T10:08:00.000-07:00

Scientists aboard the NOAA research vessel Oscar Dyson in the North Pacific have sighted a creature of great rarity and even myth: a white whale.

The white killer whale was spotted with its pod about two miles off Kanaga Volcano, part of Alaska’s Aleutian Islands, on February 23. At the time, Kodiak-based Oscar Dyson was on a research expedition for NOAA’s Alaska Fisheries Science Center, assessing pollock fish stocks near Steller sea lion haulout sites.

The white whale is a fish-eating type of killer whale, as were all the killer whales photographed on the expedition. Fish-eating killer whales are the most frequently seen whales around the Aleutian Islands during the summer. The winter sightings represent important evidence that they may be common year-round.

Holly Fearnbach, a research biologist at NOAA’s National Marine Mammal Laboratory in Seattle, was able to photograph the whale’s white fin and back. “With hundreds of killer whales documented around the Aleutian Islands, this was equivalent to finding a needle in a haystack,” she said.

“Despite the typical stormy weather that makes research operations very difficult in the winter, the scientific team on Oscar Dyson has been pulling in a huge amount of planned research data,” said Alaska Fisheries Science Center director Doug DeMaster. “Extraordinary sightings like this white whale are icing on the cake.”

Few white killer whales have ever been seen, according to Fearnbach, much less scientifically documented.

This whale is likely not a true albino because it still has signs of darker pigmented areas on its body. However, because of its prominent coloring, the white whale serves as an indicator for movements of killer whales in the North Pacific.

White killer whales have been sighted previously in the Aleutian Islands as well as in the Bering Sea and off the Russian coast. Scientists are working to confirm whether or not the whale sighted Feb. 23 is the same animal as any of those previous seen.

Besides fish and marine mammal researchers from the Alaska Fisheries Science Center, Oscar Dyson also carried a bird observer from the US Fish and Wildlife Service. All added to scientific knowledge about the marine ecosystem of the Aleutian Islands in winter.

The National Oceanic and Atmospheric Administration, an agency of the U.S. Commerce Department, is dedicated to enhancing economic security and national safety through the prediction and research of weather and climate-related events and information service delivery for transportation, and by providing environmental stewardship of our nation's coastal and marine resources. Through the emerging Global Earth Observation System of Systems (GEOSS), NOAA is working with its federal partners, more than 70 countries and the European Commission to develop a global monitoring network that is as integrated as the planet it observes, predicts and protects.

http://www.noaa.gov/

Each White Whale Has Its Individual Voice

2009-05-20T10:06:00.000-07:00

The fact that each white whale has individual voice is established by Russian scientists conducting research in the White Sea. Differences between white whales' voices can be used in estimating their number.

"White whale individuals can be distinguished by the sound of voice practically like humans," - tell V.M. Bel'kovich and S.A. Kreichi from the Shirshov Institute of Oceanology. The scientists observe the animals every year in the White Sea by the Bolshoi Solovetskii Island, where their stationary is located. There dwells a population of white whales that includes many females with calves. The acoustic system consisting of a hydrophone, amplifier, and digital recorder registers communicative calls of white whales within the range from 0.06 to 20 kHz. The stable population structure is beneficial for identifying and distinguishing individual voices of the animals.

Communicative calls of white whales can be compared to human sounds. The whales make various vocal-like, voice-like, whistling, flicking, bumping, hiccupping, and smacking sounds and noises. Therefore, methods for studying human speech are to a certain extent applicable to whales. Their calls can be arranged in blocks that can be grouped at higher hierarchical levels. Certain blocks are often repeated, which makes it possible to suggest that sounds make up syllables, and syllables make up words in whales' communication.

Using the computer program "Speech Analyzer" the researchers obtained amplitude/time, frequency/time, and spectrum/time characteristics of white whales' calls. They got especially curious about vowel-like sounds that are either short like vowels in human speech or long like a sort of singing or bleating. These sounds are most characteristic of whale individuals because of differences in their duration, pitch, and timbre. Hence, they can serve as an acoustic mark of an animal.

It is curious that white whales, like people, differ by voice pitch. In the studied population, animals with high-, moderate-, and low-pitched voices constitute 20%, 50%, and 30%, respectively. The distribution of voice pitches in white whale males and females is comparable with that in humans.

The researchers have carefully studied individual characteristic features of whale voices and verified the practical applicability of that knowledge as follows. Using their acoustic device they counted voices in a flock of white whales and estimated the number of animals at about forty, which coincided with visual survey data.

http://www.informnauka.ru/

Research Tracks Whales By Listening To Sounds

2009-05-20T10:03:00.000-07:00

Researchers have developed a new tool to help them study endangered whales -- autonomous hydrophones that can be deployed in the ocean to record the unique clicks, pulses and calls of different whale species.

Those efforts are leading to some surprising findings, including the discovery by a team of researchers of rare right whales swimming in the Gulf of Alaska.

"There has been only one confirmed sighting of a right whale in the Gulf of Alaska since 1980, so discovering them is not only surprising, it is fairly significant," said David K. Mellinger, an assistant professor at Oregon State University's Hatfield Marine Science Center in Newport. "We picked up the sounds of one whale off Kodiak Island, and several others in deep water, which is also something of a surprise, since most right whale sightings have been near-shore."

Results of these and five years of studies have been published in the January 2006 issue of the journal BioScience. Mellinger said scientists have been able to use the hydrophones to distinguish sounds made by different whale species. And some species, he added, have different "dialects" depending on where they are from. Blue whales off the Pacific Northwest sound different than populations of blue whales that live in the western Pacific Ocean, and those sound different from populations of blue whales off Antarctica.

And they all sound different than the blue whales off Chile.

"The whales in the eastern Pacific have a very low-pitched pulsed sound, followed by a tone," Mellinger said. "Other populations use different combinations of pulses, tones and pitches. The difference is really striking, but we don't know if it is tied to genetics, or some other reason.

"There are also some hybrid sounds that are rare," he added. "We don't know if they are part of a common 'language' that different populations of whales use to communicate with each other, or if they come from a confused juvenile who hasn't completely learned the complexities of communicating."

Scientists began hearing whale sounds several years ago on a U.S. Navy hydrophone network. The hydrophone system -- called the Sound Surveillance System, or SOSUS -- was used by the Navy during the Cold War to monitor submarine activity in the northern Pacific Ocean. As the Cold War ebbed, these and other military assets were offered to civilian researchers performing environmental studies.

Another Oregon State researcher, Christopher Fox, first received permission from the Navy to use the hydrophones at his laboratory at OSU's Hatfield Marine Science Center to listen for undersea earthquakes -- a program now directed by Robert Dziak.

While listening for earthquakes, the OSU researchers begin picking up sounds of ships, marine landslides -- and whales. An engineer at the center, Haru Matsumoto, then developed an autonomous hydrophone that can be deployed independently and Mellinger's colleagues placed seven of these instruments in the Gulf of Alaska about five years ago. The hydrophones can pick up right whale sounds from about 40 kilometers away -- and even farther, if the waters are shallow and the terrain even.

Using those hydrophones, Mellinger discovered a number of sperm whales living in the Gulf of Alaska in the winter. The hydrophones picked up almost half as many whale sounds as in the summer -- indicating a surprisingly robust "off-season" population.

"There are a handful of records of people spotting sperm whales in the region -- and they're all in the summer," Mellinger said. "Likewise, all of the historic whaling records are from the summer. The Gulf of Alaska is not a place you want to be in the winter. But apparently, sperm whales don't mind."

Other researchers participating in the study include Sue Moore, NOAA's Alaska Fisheries Center in Seattle; Kathleen M. Stafford, an OSU graduate now at the University of Washington; and John A. Hildebrand, Scripps Institution of Oceanography.

This spring, the researchers plan to deploy three more hydrophones in the Bering Sea next to a series of long-duration NOAA moorings. They will analyze possible connections between the appearance of the whales and ocean conditions. "We'll look at water temperature, salinity and even chlorophyll growth," Mellinger said. "Ultimately, what we hope is to be able to identify a certain water mass and know that it will lead to chlorophyll growth and an abundance of plankton, and that the whales will soon appear."

http://oregonstate.edu/

Oil, Gas Seismic Work Not Affecting Gulf Sperm Whales

2009-05-20T09:57:00.000-07:00

Noise can be irritating and possibly harmful for everything from mice to humans – and maybe even 60-foot whales in the Gulf of Mexico.

In recent years, there has been concern that man-made noise may be a cause of stress for dolphins, whales and other marine mammals, but the results of a five-year study show that noise pollution – especially noise generated by seismic airguns during geophysical exploration for oil and gas – seems to have minimal effect on endangered sperm whales in the Gulf of Mexico, say researchers from Texas A&M University who led the project and released their 323-page report today at the Houston Museum of Natural Science.

The multi-year $9 million study, the largest of its type ever undertaken and formally titled Sperm Whale Seismic Study in the Gulf of Mexico, was conducted by the Minerals Management Service and featured cooperation with the Office of Naval Research, the National Science Foundation and the National Fish and Wildlife Foundation. The project brought together researchers from eight universities, but it was managed overall by Texas A&M's Department of Oceanography, with research scientist Ann Jochens and professor Doug Biggs serving as principal investigators.

"The bottom line is that airgun noise from seismic surveys that are thousands of yards distant does not drive away sperm whales living in the Gulf," Biggs explains.

"However, some individual whales feeding at depth reduced the rate at which they searched acoustically for their prey when scientists carried out controlled exposure experiments by bringing seismic surveys close by the whales. As a result, the oil and gas industry has agreed to a best-practice attitude that seismic surveys should shut down temporarily when towed airguns come within one-third of a mile of whales or groups of whales in the Gulf."

Though not often seen, sperm whales are regular visitors to and residents in the Gulf of Mexico. They are the largest of all toothed whales and can reach lengths of 60 feet or more and live 60 years or longer. Their primary diet is squid and fish and they have been known to dive as deep as 7,000 feet. Humans no longer hunt them for their oil, but the whale in Herman Melville's classic novel Moby Dick was a sperm whale.

Sperm whales are not often seen because they prefer to stay in the deep waters of the Gulf, usually in depths of 3,000 feet or more and at least 150 miles offshore, Biggs says.

"Sperm whales go to where their food source is, and that means very deep water. So folks that do see them are marine mammal observers who ride the seismic survey vessels and the workers on the big oil and gas rigs, and even that does not happen often," Biggs adds.

The primary concern facing the scientific research group was noise – there's more of it in the world's oceans than you might think. A study by the Scripps Institution of Oceanography shows that the world's oceans are 10 times noisier since the 1960s, and at any one time, there are as many as 30,000 ships circling the globe.

Biggs says that over the course of five summers, 98 sperm whales were tagged with devices that relayed back critical data such as measurements about sound levels and behavioral aspects of whales, including tracking their movements. Of particular concern was the effect that loud low-frequency noises, such as those created by seismic activity, might have on sperm whales in the area.

Oil and gas companies prospect for subsea reservoirs by firing air guns during their seismic work, which government regulators thought might negatively affect sperm whale behavior. Also, the sheer volume of work being done in the Gulf was another concern: The Gulf of Mexico accounts for almost 70 percent of the oil and gas extracted from U.S. waters and there are thousands of oil and gas platforms in the region.

But the study found no unusual effects of controlled exposure to seismic exploration on the swimming and diving behavior by sperm whales in the Gulf, and also revealed a wealth of data about sperm whale biology and habitat.

"We now know that the sperm whales in the Gulf appear to be their own distinct stock – they show genetic and social differences from other sperm whales around the world," Biggs says.

"There are believed to be about 500 to 1,500 sperm whales that reside in the Gulf. Most of these are family groups of females and maturing young. When one family group socializes with another family group in the Gulf, they make very distinct sounds. Even though the family groups are visited by males that come into the Gulf from other oceans, their 'clicking' sounds, called codas, the Gulf sperm whales make appear to be different from most others made by sperm whale groups in other parts of the world.

"The five-year study has greatly contributed to our knowledge of sperm whales, especially those found in the Gulf of Mexico. It's also raised new questions we need to know more about, such as their feeding and breeding patterns. There's still a lot we don't know about these huge creatures."

http://www.tamu.edu/

Ecologists Home In On How Sperm Whales Find Their Prey

2009-05-20T09:54:00.000-07:00

Ecologists have at last got a view of sperm whales' behaviour during their long, deep dives, thanks to the use of recently developed electronic "dtags". According to new research published in the British Ecological Society's Journal of Animal Ecology, sperm whales – like bats – use echolocation consistently to track down their prey at depth.

Working in the Atlantic, the Gulf of Mexico and the Ligurian Sea, scientists from Woods Hole Oceanographic Institution and the University of St Andrews attached acoustic recording tags to the dorsal surface of sperm whales with suction cups. The whales were then tracked acoustically with a towed hydrophone array.

The researchers used the tags to record the sounds that sperm whales produce while foraging. As sperm whales descended from the surface, they emitted a regular series of "clicks". When the whales reach the bottom of their dive, these clicks are emitted more often, eventually merging together to form "buzzes" of sound. This pattern reflects the whales homing in on cephalopods such as squid, with the buzzes reflecting the animals' final approach when detailed information on the squid's position and movement are required, the researchers believe.

Dr Stephanie Watwood and colleagues found that sperm whales produced buzzes on every deep dive they made, in all three locations, suggesting that they are highly successful at locating prey in the dark ocean depths.

The sperm whale is the world's largest deep-diving toothed whale, feeding mainly on squid, but until now little has been known about the timing of prey detection and capture during dives.

"Due to the difficulty of observing sperm whales during their long, deep dives, little has been known about their subsurface behaviour, giving rise to an array of speculations on how sperm whales find prey, including luring, touch, passive listening, echolocation and vision. Recording vocalisations of diving sperm whales presents a non-invasive opportunity to document feeding activity." says Watwood.

http://eu.wiley.com/WileyCDA/Section/index.html

Early Whales Used Well Developed Back Legs For Swimming

2009-05-20T09:48:00.000-07:00

The crashing of the enormous fluked tail on the surface of the ocean is a “calling card” of modern whales. Living whales have no back legs, and their front legs take the form of flippers that allow them to steer. Their special tails provide the powerful thrust necessary to move their huge bulk. Yet this has not always been the case.

Reporting in the latest issue of the Journal of Vertebrate Paleontology, paleontologist Mark D. Uhen of the Alabama Museum of Natural History describes new fossils from Alabama and Mississippi that pinpoint where tail flukes developed in the evolution of whales.

“We know that the earliest whales were four-footed, semi-aquatic animals, and we knew that some later early whales had tail flukes, but we didn’t know exactly when the flukes first arose,” said Uhen. “Now we do.”

The most complete fossil described in the study is a species called Georgiacetus vogtlensis. Although not new to science, the new fossils provide some very significant new information. In particular, previously unknown bones from the tail show that it lacked a tail fluke. On the other hand, it did have large back feet and Uhen suggests that it used them as hydrofoils. Undulating the body in the hip region was the key factor in the evolution of swimming.

The very different body forms seen in the lineage of whales point to very different methods of swimming underwater. Previous studies have proposed a possible process to evolve from the ancestral form, paddling with all four legs, to the modern-day whale in which the tail oscillates up and down. Living vertebrates that are capable swimmers employ a whole range of different techniques, including five particularly well defined methods: quadrupedal paddling, paddling only using the back legs, undulation of the hips, tail undulation, and tail oscillation.

Interestingly, it had been suggested that during whale evolution each of these steps occurred in turn, but that the hip undulation stage might have been by-passed. The new discoveries indicate that the complete opposite was true, and as Uhen says “wiggling hips were a significant step in the evolution of underwater swimming in whales.”

So now we know that Elvis was not the first to owe success to undulating hips!

http://vertpaleo.org/

Is The Hippopotamus The Closest Living Relative To The Whale?

2009-05-20T09:46:00.000-07:00

Hippos spend lots of time in the water and now it turns out (or researchers argue), they are the closest living relative to whales. It also turns out, the two are swimming in a bit of controversy.
Jessica Theodor, an associate professor in the Department of Biological Sciences at the University of Calgary, and her colleague Jonathan Geisler, associate professor at Georgia Southern University are disputing a recent study that creates a different family tree for the hippo.

That research was published in Nature in December 2007 by J. G. M. Thewissen, a professor at Northeastern Ohio Universities College of Medicine, and his colleagues. Thewissen says that whales are more closely linked to an extinct pig-like animal, often known as India's pig or Indohyus, while hippos are closely related to living pigs.

But this isn't accurate according to Theodor.

"What Thewissen is saying is that Indohyus is the closest relative of whales - and we agree. Where we think he is wrong, is that he is saying that that hippos are more closely related to true pigs than they are to whales," says Theodor. "This contradicts most of the data from DNA from the last 12 or 13 years. Those data place hippos as the closest living relative to whales."

She says Thewissen did not use DNA evidence, instead used fossil evidence alone to create a family tree and reach the conclusion that hippos have more in common with pigs than whales.

"And the reason their tree is so different is simple: by excluding all the DNA information they left out all the data that shows a strong relationship between whales and hippos."

Theodor's rebuttal of Thewissen's work will appear in Nature on Thursday, March 19.

The controversy began after the new fossil of Indohyus, was discovered and written about by Thewissen and his group. This animal lived around 48 million years ago, lived in the water and fed on land.

When biologists study family trees, they traditionally rely on morphology, in other words, the shape of bones. More recently, the DNA revolution means that scientists can use DNA data as another tool to reconstruct family trees, but DNA data can't be used all the time because DNA is not available for most fossils.

"In order to get the best understanding, researchers combine the two sources of data in a single analysis. But what Thewissen and his group did, was leave one of the major ones out," says Theodor.

Before the widespread use of DNA data, hippos had been thought to be closely related to pigs, but DNA data show that whales are closely related to hippos. Geisler and Theodor argue that leaving out the DNA data not only ignores important information, it implies that the evolution of swimming evolved independently in hippos and whales, when it may have evolved only once in a common ancestor.

http://www.ucalgary.ca/

Citrus Greening Continues To Spread In Citrus Growing Areas

2009-05-20T09:44:00.000-07:00

The latest on the rapid spread of citrus greening within Florida and its potential to spread into California and other citrus growing areas will be presented during a news conference on plant diseases and issues that are of importance to California's economy and agriculture.

Citrus greening or huanglongbing (yellow shoot) is considered one of the most serious threats to the citrus industry. A bacterial disease, citrus greening affects all types of citrus species and causes infected trees to yellow, decline, and possibly die within a few years of infection. Spread by an insect, the Asian citrus psyllid, citrus greening has significantly impacted citrus production in Asia, Africa, and Brazil.

"The threat of this disease spreading to other citrus-growing states definitely exists, especially in places where the Asian citrus psyllid is already found," said Ronald Brlansky, plant pathologist at the University of Florida, Citrus Research and Education Center. In California, researchers are continually looking for evidence of the citrus psyllid. If it is found there, citrus trees will need to be closely monitored for disease symptoms.

Citrus greening can only be managed, not completely controlled. By reducing the psyllid population through the use of insecticides, the spread of the disease may be lessened. Growers are urged to become familiar with the symptoms of huanglongbing, to scout for the symptoms and to send in samples for testing.

Citrus greening has spread from eight to 23 counties since it was first found in Florida just a little more than a year and a half ago. Once citrus trees are infected, the fruit yield, rate, and quality are greatly reduced. The trees also become susceptible to other diseases and health problems. In some areas of Brazil, citrus greening has affected as much as 70 percent of the fruit rate and yield.

http://www.apsnet.org/

Graduate Student Discovers, Names Bacterium Linked To Psyllid Yellows

2009-05-20T09:42:00.000-07:00

To make a discovery and get to name it is just about every scientist's dream. For one graduate student at UC Riverside that dream already has come true.

Allison Hansen, a doctoral student in entomology, has discovered and named a new bacterial pathogen that could be responsible for "psyllid yellows," a disease that infects and kills tomato and potato plants. The disease is spread from plant to plant by the psyllid, a sap-sucking insect. This psyllid commonly is called potato psyllid or tomato psyllid, depending on the plant affected.

Hansen, who joined UCR in 2005 and expects to graduate next year, discovered the bacterium serendipitously through her research on the "symbionts" of the tomato psyllid. (A symbiont is an organism that has an intimate relationship with another organism of a different species.)

She named the pathogen "Candidatus Liberibacter psyllaurous." Liberibacter, she explained, is the genus – a category of biological classification – in which the bacterium is nested; psyllaurous means psyllid yellows in Latin.

"Allison has a special gift of looking at questions from new perspectives and recognizing relationships that others have either overlooked or missed all together," said Timothy Paine, Hansen's advisor and a professor of entomology. "This ability has enabled her to make a couple of key breakthroughs as a graduate student that have stumped other scientists for decades."

In tomato alone, psyllid yellows resulted in yield losses up to 85 percent and 50 percent in commercial tomato crops in western North America during 2001 and 2004, respectively.

"One symptom of an infected tomato or potato plant with this bacterium is yellowing of the foliage," said Hansen, whose co-advisor is Richard Stouthamer, a professor of entomology. "The saliva of the tomato psyllid has been known to cause yellowing of tomato and potato leaves. The cause of this symptom has been a mystery for over a century."

Hansen's discovery has the potential to help plant breeders develop resistant cultivars of potato and tomato.

"What we know is that the bacterium is vectored by the tomato/potato psyllid into their tomato and potato host plants, subsequently causing yellowing and death to the plant," Hansen said. "This knowledge may help growers come up with alternative strategies for controlling this pest. We're now working in the lab to confirm whether Candidatus Liberibacter psyllaurous is the psyllid yellows-causing bacterium."

The new bacterium is closely related to huanglongbing or HLB disease, also known as citrus greening disease, so named because the disease causes the citrus fruit to retain some green spots even when the fruit is ripe.

"Huanglongbing is Chinese for yellow dragon disease," Hansen explained. "Chinese farmers call the young, infected yellowing shoots of citrus 'yellow dragons' because of the symptoms this disease causes in the plant."

To date, three other HLB bacteria have been identified, all of which primarily infect citrus. Hansen mentioned that a huge scientific effort currently is underway to study HLB of citrus, a disease that is threatening to destroy Florida's citrus industry.

Hansen, Stouthamer, Paine and John Trumble, a professor of entomology at UCR, reported the discovery of the new bacterium in a research paper published online, ahead of print, on Aug. 1 in the journal Applied and Environmental Microbiology.

"Liberibacter psyllaurous could be a good model system to come up with methods for combating citrus greening disease," Hansen said.

Currently she is looking at symbiont and psyllid interactions with host plants as well as other susceptible host plants of the bacterium. She also is trying to sequence the bacterium's genome.

Her research is funded by UCR's Department of Entomology.

http://www.ucr.edu/

Growers And Homeowners Can Help Detect Citrus Disease

2009-05-20T09:39:00.000-07:00

Plant pathologists from The American Phytopathological Society (APS) report that citrus greening is spreading faster than expected and encourage growers and homeowners to aid in the detection process by alerting the appropriate agricultural officials if they suspect they have infected trees. Citrus greening, also known as huanglongbing, was recently discovered in samples collected from trees in South Florida.

Although citrus greening is not expected to have a major impact on the supply of citrus fruit this year, it is important that the spread of this disease be carefully monitored and reported, say plant pathologists from APS.

To date, citrus greening has only been detected in Florida, but residents of all citrus growing areas in the U.S. are urged to report possible infections. Residents in Florida should call the Florida Department of Agriculture's toll-free helpline at 1.800.282.5153. Other states should contact their local state department of agriculture for information. Because citrus greening is not limited to just one outbreak, plant pathologists from APS report that eradication is probably not feasible at this point.

Citrus greening is a bacterial disease that can infect all types of citrus species. The bacterium that causes this disease is spread by an insect, the citrus psyllid.

Citrus greening affects the nutrient conducting system of citrus plants causing the infected trees to yellow, decline, and possibly die within a few years. The name "huanglongbing" means "yellow dragon" which is descriptive of the yellow sectors of infected trees. The symptoms of citrus greening usually include a blotchy mottle and leaf yellowing that spreads throughout the tree with lopsided fruit that fail to color properly.

Citrus greening is often hard to detect because its symptoms are almost identical to those that occur from nutritional deficiencies. Additionally, trees infected with citrus greening will usually not express any symptoms until three to eight months after infection.

http://www.apsnet.org/

Shade Trees Getting 'Scorched' By Plant Disease

2009-05-20T09:37:00.000-07:00

Bacterial leaf scorch is severely affecting urban shade trees grown not only to provide shade, but to help clear the air, reduce noise, and improve the aesthetics in many U.S. communities, say plant pathologists with The American Phytopathological Society (APS).

According to Ann Brooks Gould, associate extension specialist at Rutgers University, New Brunswick, NJ, bacterial leaf scorch (BLS) affects many shade tree species such as American elm, red maple, sweet gum, sycamore and London plane, and a number of oak species. The disease has been found in landscapes, street plantings, and small woodlots throughout the eastern U.S. and as far west as Texas.

According to Gould, BLS affects as many as 35 percent of susceptible street and landscape oaks in some central New Jersey communities. Current loss of value plus replacement costs for older trees affected by this disease is estimated at $8,000 per tree. Landowners and tree care professionals in these locations must plan for the loss of property values and high costs of replacement as shade trees in landscapes, wood lots, and golf courses affected by BLS decline and must be removed.

BLS is caused by a bacterial pathogen, Xylella fastidiosa, which has a wide host range that includes common landscape ornamentals and weeds. X. fastidiosa is spread by insects, mainly sharpshooters.

Symptoms of BLS are very similar to those caused by environmental stresses. Because of this, the disease is often overlooked or misdiagnosed. On oak trees, BLS symptoms include scorching in late summer or early fall on leaves of all ages at about the same time. On sycamores and elms, symptoms progress from older to younger leaves. Affected leaves may curl and drop prematurely, and as the disease progresses, branches die and the tree declines. Elms may be killed outright by the disease. Other affected species eventually decline to the point where the dead branches pose a safety risk and the tree must be removed.

According to Gould, current management options of BLS in urban trees include:

Maintain plant vigor. The development of BLS is enhanced by other diseases, insects, and environmental stresses such as drought. BLS may also predispose infected plants to other disease and insect problems.

Practice sanitation. Branches that have died due to BLS should be routinely removed. Infected trees that are in a severe state of decline should also be removed.

Use tolerant plants. In areas where BLS occurs, avoid planting highly susceptible trees, and design new tree plantings with a diverse complement of tree species.

http://www.apsnet.org/

Why Some Newly Planted Trees Die

2009-05-20T09:35:00.000-07:00

Consider the cumulative stresses that transplanted trees must endure from the time they are harvested until they become established in a landscape. Multiple stress factors can mean the difference between survival and death for trees. For starters, when "balled-and-burlapped" trees are dug prior to transport, the majority of the root system is often separated from the tree. After this initial stress, trees are typically taken to a loading site and placed on trucks or trailers for shipment.

At each stage of the transplanting process, trees are exposed to mechanical shock and vibration that can further disrupt the root system and cause considerable injury.

As if these issues are not harmful enough, trees are not usually watered during transport. If they are not covered to limit evaporation, the trees are apt to suffer additional damage. Transplanted trees can also be subjected to rapidly changing temperatures and humidity levels as they are moved from sunny to shady sites, from low to high elevations, in and out of box trailers, and across plant hardiness zones—all of which may occur in the course of a few hours. All these stress factors can add up to significant trauma, shock, and even death for these vulnerable trees.

Although any one of these stress factors may be the sole cause of a tree's death or decline, it is more likely a combination of stress factors that leads to trees' reduced growth or death after planting. Water stress, mechanical damage, or extreme temperatures alone may be sufficient to severely damage or kill a transplanted tree; when these stressors are combined, the prospect of trees' survival in the landscape is greatly reduced.

Andrew K. Koeser, J. Ryan Stewart, Germán A. Bollero, and Donald G. Bullock from the University of Illinois at Urbana-Champaign, and Daniel K. Struve from The Ohio State University recently published a study in HortScience that examines the impact of stress on balled-and-burlapped trees. "We hypothesized that stresses associated with handling and transporting nursery stock during transplanting could be directly linked to reduced tree growth and survival within the first year of establishment. Identifying the specific stress factors responsible for transplant shock and when they occur is crucial if the process is to be improved", Stewart explained.

To determine the short-term impact of transplanting on health and establishment of woody plants in the landscape, the researchers studied maple trees at three critical stages in the transplanting process (initial harvest, handling, and transport) at three sites in Illinois and Wisconsin. Norway and red maples were subjected to three distinct treatments: root-pruned, handled, and transported. "Our intent was not to look at potential treatment differences between the two maple species, but rather be able to generalize our results to transplanting events of several woody species. We then used this information to identify key stages in the transplanting process that diminish transplanted tree growth and survival", the scientists said. Effects of water stress, root severance, and root-ball disruption on twig elongation and tree survival were measured for each treatment and compared with unaltered control trees.

Harvested root balls can be extremely heavy and are relatively fragile. The researchers observed visible damage of root balls during the study. "Based on the data, it appeared the majority of this damage occurred during the handling process. Results suggest rough handling before and after transport should be minimized in an effort to maximize growth and transplant success", remarked Stewart.

The scientists advise that handling should also be minimized when trees are transplanted in order to reduce stress and establishment time. They recommend careful planning to prevent unnecessary movements of trees at both the nursery loading area and landscape site and warn that if trees are placed in mulch or composted material for an extended period of time, burlap may quickly deteriorate in warm, moist substrate.

Information from this research study can be beneficial for tree growers and end-consumers alike. The resulting recommendations can translate to fewer financial losses by offering alternative handling and planting methods that enhance the health and vitality of transplanted trees.

http://www.ashs.org/

Monkeys Found To Wonder What Might Have Been

2009-05-19T00:53:00.000-07:00

Monkeys playing a game similar to "Let's Make A Deal" have revealed that their brains register missed opportunities and learn from their mistakes.

"This is the first evidence that monkeys, like people, have 'would-have, could-have, should-have' thoughts," said Ben Hayden, a researcher at the Duke University Medical Center and lead author of the study published in the journal Science.

The researchers watched individual neurons in a region of the brain called the anterior cingulate cortex (ACC) that monitors the consequences of actions and mediates resulting changes in behavior. The monkeys were making choices that resulted in different amounts of juice as a reward.

Their task was like the TV show "Let's Make a Deal" with the experimenters offering monkeys choices from an array of hidden rewards. During each trial, the monkeys chose from one of eight identical white squares arranged in a circle. A color beneath the white square was revealed and the monkey received the corresponding reward.

Over many weeks, the monkeys were trained to associate a high-value reward with the color green and the low-value rewards with other colors. After receiving a reward, the monkey was also shown the prizes he missed.

What the researchers saw was that neurons in the ACC responded in proportion to the reward -- a greater reward caused a higher response. They also found that these same neurons responded when monkeys saw what they missed. Most of these ACC neurons responded the same way to a real or imagined reward.

To measure how these responses might help the monkey to learn, the researchers kept the high reward in the same position 60 percent of the time, or moved it one position clockwise, so that a monkey could possibly notice and adapt to that pattern. The monkeys chose targets next to potential high-value targets more often than those next to low-value targets, (37.7 percent to 16.7 percent), which suggested that they understood the relationship between the high value target on the current trial and its likely location on the next trial. The monkeys learned the pattern and chose the high value more often than by a chance.

"It is significant to learn that the neurons have a dual role, because the monkey can only adapt his behavior when he gets information on both of those events, real and missed," said Michael Platt, Duke professor of neurobiology and evolutionary anthropology and senior author of the study.

People are much more likely to gamble if they see they could have won big by gambling in the past. Thus the researchers hypothesized that the monkeys would also select the target if it had offered a large reward on the previous trial and the monkey had missed it, and indeed, they observed this pattern. The effect may have reflected an increased willingness to switch to a new target, because the likelihood of switching increased with larger missed rewards, they noted.

"This was not merely a function of the high-value targets holding a positive association for the monkey," Platt said.

The monkeys' ACC neurons signaled missed reward information, and used a coding scheme in the brain that was similar to the coding used to signal real outcomes, Platt said. The researchers suspect that these neurons actually helped the monkeys to make better choices in the future.

John M. Pearson, Ph.D., of Duke Neurobiology was also an author of the paper. The study was supported by a post-doctoral fellowship from the National Institute on Drug Abuse, a Neuroscience Education Institute grant, and the Duke Institute for Brain Sciences.

http://www.duke.edu/

Coming To The Arctic Near You: The Longer, Hotter Summer

2009-05-19T00:50:00.001-07:00

In a paper that shows dramatic summer warming in arctic Alaska, scientists synthesized a decade of field data from Alaska showing summer warming is occurring primarily on land, where a longer snow-free season has contributed more strongly to atmospheric heating than have changes in vegetation.

Arctic climate change is usually viewed as caused by the retreat of sea ice, which reduces high-latitude albedo -- a measure of the amount of sunlight reflected off a surface - a change most pronounced in winter.

"Summer warming is more pronounced over land than over sea ice, and atmosphere and sea-ice observations can't explain this," said Terry Chapin, professor of ecology at the University of Alaska Fairbanks' Institute of Arctic Biology and lead author of the paper which appears in the September 22, 2005 advance online publication Science Express.

Using surface temperature records, satellite-based estimates of cloud cover and energy exchange, ground-based measurements of albedo and field observations of changes in snow cover and vegetation, Chapin and co-authors argue that recent changes in the length of the snow-free season have triggered a set of interlinked feedbacks that will amplify future rates of summer warming.

"It's the changes in season length rather than increases in vegetation that explains this observation," Chapin said. Summer warming correlates with a lengthening of the snow-free season that has increased atmospheric heating locally by an amount similar in magnitude to the regional heating expected over multiple decades from a doubling of atmospheric carbon dioxide, say the authors.

"Snowmelt is 2.5 days earlier for each decade we studied," Chapin said.

Two mechanisms explain the pronounced warming over land during the summer. First, the early snow melt increases the length of time the land surface can absorb heat energy. Second, the increase in snow-free ground permits increases in vegetation such shrubs and advances of treelines.

"Continuation of current trends in shrub and tree expansion could further amplify this atmospheric heating 2-7 times," Chapin said.

"This mechanism should be incorporated into climate models," Chapin said. Improved understanding of the controls over rates of shrub expansion would reduce the likelihood of surprises in the magnitude of high-latitude amplification of summer warming.

Researchers were funded by the National Science Foundation, Office of Polar Programs, ARCtic System Science program -- the goal ARCSS is to answer the question: What do changes in the arctic system imply for the future?

http://www.uaf.edu/

Vegetation Growth May Quickly Raise Arctic Temperatures

2009-05-19T00:46:00.000-07:00

WASHINGTON -- Warming in the Arctic is stimulating the growth of vegetation and could affect the delicate energy balance there, causing an additional climate warming of several degrees over the next few decades. A new study indicates that as the number of dark-colored shrubs in the otherwise stark Arctic tundra rises, the amount of solar energy absorbed could increase winter heating by up to 70 percent. The research will be published 7 September in the first issue of the Journal of Geophysical Research-Biogeosciences, published by the American Geophysical Union.
The study in western Alaska during the winters in 2000-2002 shows how the increasing abundance of high-latitude vegetation, particularly shrubs, interacts with the snow and affects Earth's albedo, or the reflection of the Sun's rays from the surface. The paper, which also analyzes the ramifications of continued plant growth in the tundra regions, written by researchers at the U.S. Army Cold Regions Research and Engineering Laboratory and at Colorado State University. It presents the first evidence that shrub growth could alter the winter energy balance of the Arctic and subarctic tundra in a substantial way.

The authors measured five adjacent sites in subarctic Alaska. They included areas covered by continuous forest canopy, others dotted with shrubs, and some of barren tundra. They found that mid-winter albedo was greatly reduced where shrubs were exposed and that melting began several weeks earlier in the spring at these locations, as compared to snow-covered terrain. The researchers note, however, that the shrubs' branches produced shade that slowed the rate of melting, so that the snowmelt finished at approximately the same time for all the sites they examined.

Matthew Sturm, lead author of the study, notes that warming in the region seems to have stimulated shrub growth, which further warms the area and creates a feedback effect that can promote higher temperatures and even more growth. This feedback could, in turn, accelerate increases in the shrubs' range and size over the four million square kilometer [1.5 million square mile] tundra and effect significant changes over the region.

"Basically, if tundra is converted to shrubland, more solar energy will be absorbed in the winter than before," Sturm says. And while previous research has shown that warmer temperatures during the Arctic summer enhance shrub growth, "our study is important because it suggests that the winter processes could also contribute to and amplify the rate of the [growth]."

Sturm cites satellite and photographic evidence showing increasing plant growth across the Alaskan, Canadian, and Euro-Asian Arctic and notes that continued warming will likely produce thicker stands of brush that protrude above the snow. The new, brushy landscape would replace the smooth, white environment that currently dominates the Arctic during its 8-10 month winter.

In addition, the increasing shrub cover would impact more than just the energy balance in the Arctic. With nearly 40 percent of the world's soil carbon is stored in Arctic soils, any change in vegetation and energy is likely to trigger a response in the Arctic carbon budget. Scientists are still trying to understand the nature of this response, but Sturm and his coauthors conclude that the feedback effects they describe would undoubtedly accelerate its rate. They conclude that combined effects of increasing shrubs on both energy and carbon could change the Arctic in a way that affects the rest of the world.

http://www.agu.org/

Tundra Disappearing At Rapid Rate

2009-05-19T00:44:00.000-07:00

Forests of spruce trees and shrubs in parts of northern Canada are taking over what were once tundra landscapes--forcing out the species that lived there. This shift can happen at a much faster speed than scientists originally thought, according to a new University of Alberta study that adds to the growing body of evidence on the effects of climate change.
The boundary, or treeline, between forest and tundra ecosystems is a prominent landscape feature in both Arctic and mountain environments. As global temperatures continue to increase, the treeline is expected to advance but the new research shows that this shift will not always occur gradually but can surge ahead.

"The conventional thinking on treeline dynamics has been that advances are very slow because conditions are so harsh at these high latitudes and altitudes," said Dr. Ryan Danby, from the Department of Biological Sciences. "But what our data indicates is that there was an upslope surge of trees in response to warmer temperatures. It's like it waited until conditions were just right and then it decided to get up and run, not just walk."

Danby and Dr. David Hik, also from the Faculty of Science, reconstructed changes in the density and altitude of treeline forests in southwestern Yukon over the past 300 years. Using tree rings, they were able to date the year of establishment and death of spruce trees and reconstruct changes in treeline vegetation. The study is published in the "Journal of Ecology."

They found that a rapid change in response to climate warming during the early mid 20th century was observed at all locations. Treeline advanced considerably--as much as 85 metres elevation--on warm, south-facing slopes and tree density increased significantly--as much as 65 per cent--on cooler, north-facing slopes.

"The mechanism of change appears to be associated with occasional years of extraordinarily high seed production--triggered by hot, dry summers--followed by successive years of warm temperatures favourable for seedling growth and survival," said Danby.

Widespread changes to treelines could have significant impacts, says Danby. As tundra habitats are lost and fragmented, species and habitats are forced to move upwards as well. "The problem is that in mountainous areas you can only go so high so they get forced into smaller and smaller areas," said Danby.

These changes are of particular importance in these northern regions where First Nation people still rely heavily on the land, says Danby. Tundra species like caribou and sheep populations, which are important parts of that lifestyle, have declined across southwestern Yukon. As treeline advance, the reflectance of the land surface declines because coniferous trees absorb more sunlight than the tundra. This light energy is then re-emitted to the atmosphere as heat. This sets up a "positive feedback," the same process that is associated with the rapidly decaying Arctic ice cap.

"These results are very relevant to the current debate surrounding climate change because they provide real evidence that vegetation change will be quite considerable in response to future warming, potentially transforming tundra landscapes into open spruce woodlands," said Danby, who will also be participating in an International Polar Year project that will be examining treeline dynamics across the circumpolar north.

Dr. Hik is also executive director of the Canadian International Polar Year secretariat at the University of Alberta.

http://www.ualberta.ca/

If Northern Trees Suffer Because Of Global Warming, Southern Trees May Still Be Slow To Replace Them

2009-05-19T00:41:00.000-07:00

If a warmer Wisconsin climate causes some northern tree species to disappear in the future, it's easy to imagine that southern species will just expand their range northward as soon as the conditions suit them.
The reality, though, may not be nearly so simple. A model developed by University of Wisconsin-Madison forest ecologists Robert Scheller and David Mladenoff suggests that while certain northern species, such as balsam fir, spruce and jack pine, are likely to decline as the state's climate warms, oaks, hickories and other southern Wisconsin trees will be slow to replace them.

Why? Not only is warming expected to outpace the speed at which southern trees can migrate northward, but barriers to dispersal - particularly agricultural lands - will also likely delay their progress, says Mladenoff.

"The result is that northern forest biomass in the future - that is, the standing amount of forest - could decrease, because the trees that are there now will be experiencing less than optimal conditions," he says. "And the southern species aren't going to fill in as quickly as we'd like." He and Scheller report their findings in the current issue of Climate Research.

Mladenoff explains that trees "move" into new areas by producing seeds, which are then carried over short distances by wind, birds or mammals. Under the right conditions, dispersed seeds then grow into seedlings and eventually mature trees, which produce their own seeds to start the process all over again.

Already a slow process, dispersal becomes even slower when forests are broken up by farmland and urban areas - or fragmented - like they are in Wisconsin. Not only is less suitable habitat available overall, but patches of it can also be widely scattered, making it tough for seeds to cross the gaps. In particular, Mladenoff points to the wide band of agricultural land that runs across the middle of the state as a major obstacle to the northward migration of southern trees.

To arrive at their conclusions, Scheller and Mladenoff fed current satellite classification and forest inventory data for a 1.5 million-hectare area of northwestern Wisconsin into a model, LANDIS-II, that's designed to predict how landscapes will respond to climate shifts. Using two well-established sets of future climate predictions, they then examined changes in parameters such as forest succession, seed dispersal and tree growth during the next 200 years.

In the face of the scientists' predictions, is there anything woodland managers can do now? Mladenoff cautions people not to make any drastic management changes. But one thing managers might begin to try is assisted migration: testing how certain southern Wisconsin species - or even different genetic stocks of the same species - do when planted up north on a trial basis. A prime candidate for experiments like this might be sugar maple, says Mladenoff, which is already widely distributed across Wisconsin and is projected to "do OK" on moist soils in the north when the climate warms.

The state might even consider bringing back the field trials that used to go on routinely in the 1950s and '60s, he says, in which researchers would collect genetic variants of individual tree species all over the state and then plant them in many locations to see where they did best. Although time-consuming, an approach like this could help ease some of the uncertainty we're facing now.

"A lot of this is about our incomplete knowledge of how genetically diverse some species are," Mladenoff says, "and how adaptable they may be in different climates."

http://www.wisc.edu/

Climate Change Driving Michigan Mammals North

2009-05-19T00:38:00.000-07:00

Some Michigan mammal species are rapidly expanding their ranges northward, apparently in response to climate change, a new study shows. In the process, these historically southern species are replacing their northern counterparts.
The finding, by researchers at the University of Michigan, Michigan State University and Ohio's Miami University, appears in the June issue of the journal Global Change Biology.

"When you read about changes in flora and fauna related to climatic warming, most of what you read is either predictive—they're talking about things that are going to happen in the future—or it's restricted to single species living in extreme or remote environments, like polar bears in the Arctic," said lead author Philip Myers, professor of ecology and evolutionary biology at U-M. "But this study documents things that are happening right now, here at home."

What will be the ultimate impact of Michigan's changing mammal communities?

"We're talking about the commonest mammals there, mammals that have considerable ecological impact," Myers said. "They disperse seeds, they eat seeds, they eat the insects that kill trees, they disperse the fungus that grows in tree roots that is necessary for trees to grow, and they're the prey base for a huge number of carnivorous birds, mammals and snakes. But we don't know enough about their natural history to know whether replacing a northern species with a southern equivalent is going to pass unnoticed or is going to be catastrophic. It could work either way.

"What we can say is that the potential is there for serious changes to happen, and it would be really smart of us to figure it out, but that will require a lot of detailed, focused ecological research."

In the study, Myers and coworkers analyzed distribution and abundance records of opossums and eight species of small forest rodents. In addition to data collected by live-trapping animals over the past 30 years, the researchers relied heavily on specimens and notes in research museums including the U-M Museum of Zoology and the Michigan State University Museum.

"Museum collections have been underutilized in studying the effects of climate change," Myers said. "We're fortunate in Michigan to have an amazing resource in the U-M Museum of Zoology collection, which contains great records of thousands of Michigan species from hundreds of locations, sampled over the past 100 years."

One study area proved especially valuable for long-term comparisons. The Huron Mountain Club, an 18,000-acre tract of pristine forest in Michigan's Upper Peninsula owned by a private association, includes a 6,400- acre research area where scientists are allowed to carry out field work. The non-profit Huron Mountain Wildlife Foundation has funded three animal surveys there: the first between 1939 and 1942, the second in 1972-1973 and the most recent in 2004-2005, when U-M graduate student Allison Poor Haraminac used methods and trapping grids like those used in the earlier studies.

Combining trapping data from Huron Mountain Club and other locations with museum material and road kill reports, the researchers ended up with a total of 50,000 records, 14,614 of which were for the nine mammal species in the study. When those records were analyzed, they painted a clear picture of mammals on the move.

Of the nine mammal species examined, four have established strongholds or increased in abundance, while five have declined. The increasing species—white-footed mice, southern flying squirrels, eastern chipmunks and common opossums—all are southern species, while the declining species—woodland deer mice, southern red-backed voles, northern flying squirrels, woodland jumping mice, and least chipmunks—are all northern species.

The south-to-north expansion pattern is what you'd expect if climate change is driving the advance, but could there be other explanations, such as forest regeneration or human influence?

"Clearly there's a lot more forest now than in the late 1800s and early 1900s, when logging and fires almost completely destroyed the forests of the northern Great Lakes region," Myers said. "But that doesn't work as an explanation for the patterns we see, because the species that are moving in and becoming more common are actually ones that do very well when forests are cut over." What's more, the change is happening even in the uncut forest of the Huron Mountain Club.

Similarly, increases in human population and the changes in land use that go along with them can't completely explain the changing mammal distribution and abundance patterns, Myers said. For one thing, the mammal changes are not restricted to habitats that have been disturbed by human habitation. For another, they're seen both in the Lower Peninsula, where the human population has increased over the past 50 years, and in the Upper Peninsula, where the trend has been in the opposite direction.

That leaves warming climate as the likely cause. But has such warming actually occurred in Michigan? To investigate, the researchers downloaded maximum and minimum daily temperatures from the National Climate Data Center for 16 weather stations in the Upper Peninsula, where changes in the small forest rodent community have been especially pronounced. They then calculated monthly averages for minimum and maximum daily temperatures for each year between 1970 and 2007 for each station and for the region as a whole.

Across all 16 sites, average annual minimum daily temperatures increased significantly over the 37-year period. Average annual maximum daily temperatures also rose, although not as dramatically.

The research team's results and conclusions dovetail with those of other groups that have found northward expansions of particular species in Wisconsin and Ontario and a shift from lower to higher elevations in the Yosemite National Park.

In addition to Myers and Haraminac, researchers involved in the study are Barbara Lundrigan of Michigan State University, Susan Hoffman of Miami University and U-M undergraduate Stephanie Seto. The research was supported by the Huron Mountain Wildlife Foundation, the Michigan Department of Natural Resources, Miami University, Michigan State University, the U-M Undergraduate Research Opportunities Program, Rackham Graduate School and the U-M Biological Station.

http://www3.interscience.wiley.com/journal/121634609/abstract?CRETRY=1&SRETRY=0

Ocean Fish Farming Harms Wild Fish, Study Says

2009-05-18T01:04:00.000-07:00

Farming of fish in ocean cages is fundamentally harmful to wild fish, according to an essay in this week's Conservation Biology.
Using basic physics, Professor Neil Frazer of the Department of Geology and Geophysics at the University of Hawaii at Manoa explains how farm fish cause nearby wild fish to decline. The foundation of his paper is that higher density of fish promotes infection, and infection lowers the fitness of the fish.

For wild fish, lowered fitness means more difficulty finding food and escaping predators, causing higher death rates. But farmed fish are not only fed, they are also protected from predators by their cage, so infected farm fish live on, shedding pathogen into the water. The higher levels of pathogen in the water cause the death rates of wild fish to rise.

The above paradigm explains recently documented declines of wild fish in areas with sea-cage farm fish.

"Sea lice are an important example of disease transfer in ocean fish farming," explains Frazer. "Sea lice are tiny crabs that attach to marine fishes, eating their skin and sometimes deeper tissue. Skin is important to fish because they need to keep their tissues less salty than the ocean. Also, when lice puncture the skin they create an entry point for other infections. So wild fish weakened by lice have more difficulty finding food and escaping predators."

A female sea louse can produce over a thousand larvae during her life. Larvae drift in the ocean and a lucky few of them drift close enough to a fish to attach. Most larvae die without ever finding a fish. In a fish farm environment, a larva's chance of finding a fish increases, so more larvae survive to become lice, and those lice put more larvae into the water. With more larvae in the water, more wild fish become infected and die as a result.

Larger numbers of lice are especially dire for salmon because juvenile salmon must transit coastal areas where salmon farms are located. Juvenile pink and chum salmon (Pacific species) suffer most because they spend much of their early life in coastal waters, and they are so small at ocean-entry that infection by even one or two lice can be fatal.

The calculations in the paper show that even if lice levels on farm fish are controlled by medication, local wild fish still decline. Also, there is a critical stocking level of farmed fish. If a sea-cage system is stocked above the critical level, local wild fish decline to extinction. Long story short — growing farm fish in sea cages can't save wild fish, but it can easily destroy them.

Even Fish Don't Swim Well When They're Young

2009-05-18T01:02:00.001-07:00

Do you remember learning to swim? Thrashing around, floundering, until suddenly it all clicks into place and a few feeble strokes of doggy-paddle propel you away from your parent's arms. Surely, you think, fish must be born as expert swimmers. Actually, fish larvae are pretty feeble when it comes to an efficient mode of swimming called 'burst-and-coast'. Dr Ulrike Müller from Wageningen University studies how fish swim: "Fish larvae are the most critical life history stage. In marine fish more than 99% of the mortality occurs in the larval stage so anything that might explain what holds them back is useful". Müller presented her research recently at the Society for Experimental Biology's Annual Main Meeting in Canterbury.
The 'burst-and-coast' method of swimming involves alternating stages: the fish power forward in a 'burst' and then hold their body straight to 'coast'. Dr Müller and her colleagues might have found what it is that prevents larvae of the zebrafish from reaching top speeds: the larvae cannot maintain their body in a horizontal position while coasting. The research team think this is because larvae don't have the help of an adult swimbladder and have only small, ineffective side-fins. This lack of control in early days means that the larvae suffer a lot of drag during the coasting phase and this could be something that affects other types of fish. "Many fish larvae hatch without fully formed pectoral fins and all hatch without a swimbladder, so similar problems could occur for them", predicts Müller.

This conclusion is all the more profound because it refutes two previous theories of poor hatchling swimming, one focusing on the burst phase and the other on the coast. The former of the two explanations suggests that because the larvae are not very heavy they may not gain much momentum in the burst phase to carry over into the coast phase, while the latter theory states that when the larvae are very small they experience the water in a different way; it appears thicker, like syrup and harder to swim in. "Momentum can explain some of the poor swimming in larvae, but not all, and the difference in coasting ability cannot be explained by differences in body length either", Müller argues.

Hopefully Müller's findings about pectoral fins and swimbladders can be used to reduce fish mortality rates. "Fish breeding programs cannot offer their larvae swimming lessons, but once we understand which behaviours cause the fish larvae the most trouble, then it is easier to adjust rearing schemes in aquaculture and to lend a hand to endangered species", she says.

Genetic Switches Help Fish Adjust To Fresh And Salty Water

2009-05-18T01:01:00.000-07:00

UC Davis researchers have discovered two key signals that tell fish how to handle the stress of changing concentrations of salt as they swim through different waters.
Not many fish can travel between saltwater and freshwater. To maintain the right internal salt level, their gills must pump up salt from freshwater but excrete it in the ocean.

"Fish that can survive both environments are able to resist many kinds of stress," said Dietmar Kueltz, an assistant professor of animal science.

Kueltz's team wants to understand the chain of signals that control the stress response in these fish. They experimented with tilapia, moving the fish directly from a freshwater tank to one holding seawater. They observed a rapid increase in the levels of two transcription factors: proteins that flip specific genes on and off in the tilapia's gills.

Now, Kueltz says, his team will use its findings to identify the next steps in the pathway of stress signals.

"When you find transcription factors regulated by stress, you have a tool in your hands that you can use to search for genes" further down the pathway, he explained. "This work will help us understand why some fish tolerate stress well," said Kueltz. Such fish might be better able to survive other stresses, "like climate change or exposure to toxins from agricultural runoff."

Kueltz's work was published in the Jan. 10 online edition of the Proceedings of the National Academy of Sciences. His work was funded by the National Science Foundation.

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Adapted from materials provided by University Of California - Davis.

Freshwater Fish Invasions The Result Of Human Activity

2009-05-18T00:59:00.001-07:00

Globally, invasive species represent a major threat to native species. A new paper* shows that, for rivers and lakes, where these invasions occur is predicted by human activity; find an area where economic activity is high and, in nearby lakes and rivers, up to a quarter of species will be migrants to the region.

In the first global analysis of invasions in aquatic habitats, Fabien Leprieur, Olivier Beauchard, and colleagues investigate what factors can predict invasion events and find that human activity is to blame.

Prior to this work, ecologists have debated the relative importance of human activity and intrinsic features of an ecosystem when trying to explain the distribution of invasive species. Researchers have suggested that the number of native species would predict the number of invasive species settling in an area.

This is because either an environment that is good for fish generally, and therefore hosts lots of natives, would be good for invaders too; or, conversely, because an environment that was host to many natives would be"full" to hopeful migrants.

Leprieur and colleagues from France, Belgium, and Canada investigated the fish species found in over 1000 river basins and found that the number of native species does not correlate with the number of invasive species.

Instead, they found that invasion was related to gross domestic product, with higher human population density, and with nearby urbanized land. This raises serious concerns for the future of many aquatic ecosystems as the rate of global economic expansion continues to rise, predicting an increase in invasive species and, with it, an increase in the extinction of native animals.

*Citation: Leprieur F, Beauchard O, Blanchet S, Oberdorff T, Brosse S (2008) Fish invasions in the world's river systems: When natural processes are blurred by human activities.

Controlling Invasive Species: How Effective Is The Lacey Act?

2009-05-18T00:58:00.000-07:00

Andrea Fowler, David Lodge, and Jennifer Hsia (University of Notre Dame) examined the efficacy of the Lacey Act in their research communication, "Failure of the Lacey Act to protect US ecosystems against animal invasions."
With over 100 years on the books (passed in 1900), the Lacey Act is the main legal defense against invasive animal species. The "injurious wildlife provision" of the Lacey Act seeks to regulate foreign invasive species that may damage ecosystems, replace native populations, and kill off valuable natural resources and fisheries.

"If the US is to reduce the probability of future damage from invasive animal species, revision or replacement of the Lacey Act's injurious wildlife provision is essential," say the authors. "The contemporary threat of invasive species has far outstripped current authority and practice under this statute."

Examining all Federal Register documents, Fowler and colleagues searched the listed names of organisms, references to the Lacey Act, and references to injurious wildlife to determine which species were listed, considered for listing, and either added or not added to the list.

Many animals were already established when they were added to the list and continued to spread after their listing. The most common way to begin the process of listing a species in the last 25 years has been by petitioning the U.S. Fish and Wildlife Service. However, by March 1, 2007, when the authors wrote the paper, it took an average of more that three and a half years to list a species in this way.

According to the report, the lack of an efficient and consistently applied risk assessment procedure undermine the Lacey Act. Currently, most imported species only need to be declared to customs or permitted through the US Fish and Wildlife Service. The act was expanded from mammals and birds to include mollusks, crustaceans, reptiles, and amphibians in the late 1960's and early 1980's. In the 1970's there was a movement to limit importation to a list of low-risk wildlife, but the list was never implemented.

Fowler et. al. point out that the Lacey Act contains no authority or funding to manage the spread of established wild invasive species, which will do little to slow down organisms already present in the US.

The researchers suggest that prescreening, as well as switching from the use of a list of banned animals to approved species, would better protect the nation's environment and natural resources.

The study appears in the September issue of Frontiers in Ecology and the Environment.