January 29, 2010, 8:07 AM CT

Bees recognize human faces

Going about their day-to-day business, bees have no need to be able to recognise human faces. Yet in 2005, when Adrian Dyer from Monash University trained the fascinating insects to associate pictures of human faces with tasty sugar snacks, they seemed to be able to do just that. But Martin Giurfa from the Universit de Toulouse, France, suspected that that the bees weren't learning to recognise people. 'Because the insects were rewarded with a drop of sugar when they chose human photographs, what they really saw were strange flowers. The important question was what strategy do they use to discriminate between faces,' explains Giurfa. Wondering whether the insects might be learning the relative arrangement (configuration) of features on a face, Giurfa contacted Dyer and suggested that they go about systematically testing which features a bee learned to recognise to keep them returning to Dyer's face photos. The team publish their discovery that bees can learn to recognise the arrangement of human facial features on 29 January 2010 in the Journal of Experimental Biology at http://jeb.biologists.org.

Teaming up with Aurore Avargues-Weber, the team first tested whether the bees could learn to distinguish between simple face-like images. Using faces that were made up of two dots for eyes, a short vertical dash for a nose and a longer horizontal line for a mouth, Avargues-Weber trained individual bees to distinguish between a face where the features were cramped together and another where the features were set apart. Having trained the bee to visit one of the two faces by rewarding it with a weak sugar solution, she tested whether it recognised the pattern by taking away the sugar reward and waiting to see if the bee returned to the correct face. It did......... Posted by: Kelly      Read more         Source

January 28, 2010, 8:07 AM CT

Figs and fig wasps

Figs and fig wasps have evolved to help each other out: Fig wasps lay their eggs inside the fruit where the wasp larvae can safely develop, and in return, the wasps pollinate the figs.

But what happens when a wasp lays its eggs but fails to pollinate the fig?

The trees get even by dropping those figs to the ground, killing the baby wasps inside, reports a Cornell University and Smithsonian Tropical Research Institute study reported in the Proceedings of the Royal Society B (published online Jan. 13).

The findings suggest that when one species in a mutually beneficial relationship fails to hold up its end of the bargain, sanctions appears to be a necessary part of maintaining the relationship.

"We want to know what forces maintain this 80 million-year-old mutualism between figs and their wasp pollinators," said main author Charlotte Jandr, a Cornell graduate student in neurobiology and behavior, who conducted the study as a Smithsonian Tropical Research Institute predoctoral fellow. Edward Allen Herre, a staff scientist at the Smithsonian institute in Panama, co-authored the paper.

"What prevents the wasps from cheating and reaping the benefits of the relationship without paying the costs?" Jandr added.

More than 700 species each of fig trees and wasps have co-evolved in the tropics worldwide, with each fig tree species having its own species of pollinating wasp. Jandr worked on six fig tree-fig wasp pairs for the study. Some wasp species passively carry pollen that sticks to their bodies, while others actively collect pollen in special pouches......... Posted by: Kelly      Read more         Source

January 28, 2010, 8:02 AM CT

Deadly fish virus now found in all Great Lakes

A deadly fish virus that was first discovered in the Northeast in 2005 has been found for the first time in fish from Lake Superior, report Cornell researchers. That means that the virus has now been documented in all of the Great Lakes.

The viral hemorrhagic septicemia virus (VHSV), which causes fatal anemia and hemorrhaging in a number of fish species, poses no threat to humans, said Paul Bowser, professor of aquatic animal medicine at Cornell's College of Veterinary Medicine.

Bowser and his colleagues recently tested 874 fish from seven sites in Lake Superior in collaboration with the U.S. Geological Survey (USGS) Western Fisheries Research Center in Seattle. Fish from Paradise and Skanee in Michigan and St. Louis Bay and Superior Bay in Wisconsin tested positive. Some of the results have been corroborated by other laboratories; others have tests still under way.

The virus, which has been identified in 28 freshwater fish species in the Great Lakes watershed, has reached epidemic proportions in the Great Lakes and threatens New York's sport-fishing industry, said Bowser, estimated to contribute some $1.4 billion annually to New York's economy.

"People come from all over the eastern United States to fish the Great Lakes," said Bowser, noting that the virus has also been found in a few inland waters as well, including lakes, streams and a family-owned earthen pond. "The economy of a number of of these areas ebbs and flows with the season and perceived value of outdoor recreational opportunities. The value of these opportunities is dependent on how successful we are at managing the health of wild fish. On a worldwide basis, VHSV is considered one of the most serious pathogens of fish, because it kills so a number of fish, is not treatable and infects a broad range of fish species"......... Posted by: Kelly      Read more         Source

January 27, 2010, 8:19 AM CT

The Low Calorie Pet Foods

Dog and cat owners buying weight-control diets for their overweight pets are faced with a confusing two hundred percent variation in calorie density, recommended intake, and wide range cost of low-calorie pet foods, as per a research studyby the Cummings School of Veterinary Medicine at Tufts University.

The study, published this month in the Journal of the American Veterinary Medical Association, examined nearly 100 commercially available diets with weight management claims. Among their findings is that dry dog foods range in calorie density from 217 to 440 kilocalories per cup (kcal/cup) and a recommended intake that ranged from 0.73 to 1.47 times the dog's resting energy requirement. The diets also varied wildly in price-from 4 cents to more than $1.10 per kilocalorie.

Similar findings were made in wet dog food (189-398 kcal/can) and cat food (235-480 kcal/cup) marketed for weight control. The results appears to be significant for owners whose cats or dogs are overweight or obese, as per Lisa M. Freeman, DVM, PhD, DACVN, the study's co-author along with 2010 Cummings School graduate Deborah E. Linder, DVM. Nearly 50% of domesticated animals are overweight or obese.

"There is so much information-and misinformation-about pet foods, it's understandable that people are confused about what to feed their dogs and cats," said co-author Dr. Lisa Freeman, professor of nutrition at Tufts University's Cummings School of Veterinary Medicine. "To counteract these myths, people are accustomed to turning to the labels on food-but, as this study shows, packaging might not always be a reliable source of information"......... Posted by: Kelly      Read more         Source

January 27, 2010, 8:14 AM CT

Environmental threats to blue crabs

The Atlantic blue crab, Callinectes sapidus, long prized as a savory meal at a summer party or seafood restaurant, is a multi-million dollar source of income for those who harvest, process and market the crustacean along the U.S. Atlantic and Gulf coasts. Unfortunately, the blue crab population has been declining in recent years under the assault of viruses, bacteria and man-made contaminants. The signs of the attack often are subtle, so scientists from the National Institute of Standards and Technology (NIST) and the College of Charleston (CofC) are at work trying to identify the clues that will finger specific, yet elusive, culprits.

Pathogens and pollutants impair the blue crab's metabolic processes, the chemical reactions that produce energy for cells. These stresses should cause tell-tale changes in the levels of metabolites, small chemical compounds created during metabolism. Working at the Hollings Marine Laboratory (HML) in Charleston, S.C., the NIST/CofC research team is using a technology similar to magnetic resonance imaging (MRI) to identify and quantify the metabolites that increase in quantity under common environmental stresses to blue crabsmetabolites that could be used as biomarkers to identify the specific sources.

In a recent paper in Metabolomics,* the HML research team describes how it used nuclear magnetic resonance (NMR) spectroscopy to study challenges to one specific metabolic process in blue crabs: oxygen uptake. First, the scientists simulated an environmentally acquired bacterial infection by injecting crabs with the bacterium Vibrio campbellii. This pathogen impairs the crab's ability to incorporate oxygen during metabolism. Using NMR spectroscopy to observe the impact on metabolite levels, the scientists observed that the yield of glucose, considered a reliable indicator of mild oxygen starvation in crustaceans, was raised......... Posted by: Kelly      Read more         Source

January 25, 2010, 8:04 AM CT

Bat researchers no longer flying blind

Scientists at The University of Western Ontario (Western) led an international and multi-disciplinary study that sheds new light on the way that bats echolocate. With echolocation, animals emit sounds and then listen to the reflected echoes of those sounds to form images of their surroundings in their brains.

The team used state-of-the-art micro-computed tomography systems at the Robarts Research Institute in London, Ontario to collect detailed 3D scans of the internal anatomy of 26 different bats, representing 11 different evolutionary lineages. This non-destructive technique allowed scientists to identify a bone that connects the larynx to the bones that surround and support the eardrum in bats. Some bats use their larynx to generate echolocation (biosonar) signals, allowing them to operate at night; other bats use tongue clicks to achieve the same purpose.

The research team discovered that the correlation between the larynx and the ear via the stylohyal bone in the hyoid chain was unique to bats that used laryngeal echolocation. This observation makes it possible to distinguish bats that produce echolocation signals with their larynx from bats that do not echolocate and those that use tongue clicks. The results of the research will appear this week in the journal Nature, entitled "A Bony Connection Signals Laryngeal Echolocation in Bats"......... Posted by: Kelly      Read more         Source

January 25, 2010, 0:04 AM CT

Risky business for toads under threat from fungus

Midwife toads that live in the mountains are highly likely to die from a serious fungal infection, called chytridiomycosis, whereas their infected relatives in the lowlands are not, as per new research published recently in Ecology Letters

The authors of the study, from Imperial College London, the Zoological Society of London and the BiodivERsA project RACE, say their findings suggest conservationists appears to be able to limit the impact of the disease in the mountains by ensuring tourists do not transfer it between lakes.

During the five year study, the scientists observed that no midwife toads at low altitudes died as a result of fungal infection, whereas up to 100 per cent of those at high altitudes died. The mortality rate of toads at high altitudes fluctuated over the five years.

The fungus Batrachochytrium dendrobatidis (Bd), also known as chytrid fungus, grows in the skin of amphibians, causing a disease called chytridiomycosis. The fungus has caused a number of species of frog and toad to become extinct and human activity has spread the fungus across the world, affecting an estimated 50 per cent of amphibian species.

Eventhough infection commonly is invisible to the naked eye, it can cause skin discolouration and ulceration and lead to convulsions. Prior research shows that infection kills amphibians by causing heart failure. The fungus is especially prevalent in Australia and the Americas, where its spread is well studied. However, little was known about Bd in Europe before today's study......... Posted by: Kelly      Read more         Source

January 24, 2010, 10:12 AM CT

An overview of safe and effective colonic treatments

The colon is an important part of our internal organ system. It does the critical work of absorbing water and nutrients as well as eliminating waste matter. Regular adults can carry anywhere between 5 to 45 pounds of waste in their colon. This waste matter should be removed so that normal bowel processes can continue unhindered. If for any reason the colon is unable to eliminate waste matter then it can lead to a number of medical complications like hemorrhoids, constipation and ulceration colitis. This is one should get one's colon cleaned periodically.

There are many types of colonic treatments. These include colonic irrigation, enemas, oxygen-based cleansers, laxatives and herbal supplements. Not all of them are equally effective and different people react in different manner to the various types of aforementioned treatments. Hence what works very well for one, may not work as effectively for the other. A brief discussion of the treatments would help clarify matters.

In colonic irrigation a tube is inserted into the anus. Then water is flushed into the colon through this tube. This ensures removal of compacted matter from the large intestines. Enema is one of the oldest methods of cleaning the colon but it only cleans the lower part of the colon. Oxygen based cleansers use an oxidation reduction process to melt compacted waste matter. Laxatives are only a symptomatic treatment of constipation and there long term use is not recommended. Finally herbal supplements are like laxatives only but since they are composed of natural ingredients they do not have any side effects and are suitable for the elderly. ........ Posted by: Janet      Read more         Source

January 22, 2010, 8:17 AM CT

Withstanding invasion

An international research team has studied the distribution of plant species in mountainous environments. The study shows that mountain plant communities are not especially resistant to invasion by exotic species. The researchers also warn that these appears to become more aggressive as global warming gets a grip.

In 2005, researchers from various science centres in Spain, Gera number of, Switzerland, Australia, the United States and Chile created the Mountain Invasion Research Unit (MIREN) in order to study the distribution of exotic species in high mountain species and to design experiments to confirm the invasive capacity of certain species in high mountain environments.

"These plant communities in Alpine environments have until now not been thought especially vulnerable to this kind of environmental disturbance", Jos Ramn Arvalo, one of the authors of the study and a researcher at the Department of Ecology of the University of La Laguna, tells SINC. However, the experiments show clearly "that the beliefs about this supposed protection and mountain species' resistance to invasive species is erroneous", he adds.

The study, published recently in Frontiers in Ecology and The Environment, and which is part of the work done by MIREN, has made it possible to identify the factors that make plants in these areas more vulnerable to invasion by other species......... Posted by: Erica      Read more         Source

January 22, 2010, 8:05 AM CT

Sexual reproduction versus asexual reproduction

Living organisms have good reason for engaging in sexual, rather than asexual, reproduction as per Maurine Neiman, assistant professor of biology in the UI College of Liberal Arts and Sciences and researcher in the Roy J. Carver Center for Genomics.

In an article published in a recent issue of the journal Molecular Biology and Evolution, she and her colleagues, including John M. Logsdon Jr., associate professor of biology, examined the theory that sexual reproduction, while requiring more time and energy than asexual reproduction, is also much more common among living organisms and, therefore, must be very beneficial.

The study looked at sexual, as well as asexual, varieties of a New Zealand freshwater snail (left), Potamopyrgus antipodarum, by sequencing mitochondrial genomes and observed that the sexually reproducing snails had accumulated harmful DNA mutations at about half the rate of the asexual snails.

"This is the first study to compare mutation accumulation in a species where sexual individuals and asexual individuals regularly coexist, and thus provides the most direct evidence to date that sex helps to counter the accumulation of harmful mutations," said Neiman.

Neiman plans to continue her evolutionary biology research such that a clearer understanding of the advantages of sex will offer a better understanding of the value of preserving genetic diversity within and among populations, species, and ecological communities......... Posted by: Kelly      Read more         Source