October 11, 2010, 7:28 AM CT

Monarch butterflies use medicinal plants

Monarch butterflies appear to use medicinal plants to treat their offspring for disease, research by biologists at Emory University shows. Their findings were published online Oct. 6 in the journal Ecology Letters.

"We have shown that some species of milkweed, the larva's food plants, can reduce parasite infection in the monarchs," says Jaap de Roode, the evolutionary biologist who led the study. "And we have also observed that infected female butterflies prefer to lay their eggs on plants that will make their offspring less sick, suggesting that monarchs have evolved the ability to medicate their offspring." (See interview with de Roode here: http://tinyurl.com/3995m3u).

Few studies have been done on self-medicine by animals, but some researchers have theorized that the practice appears to be more widespread than we realize. "We think that our experiments provide the best evidence to date that animals use medication," de Roode says.

"The results are also exciting because the behavior is trans-generational," says Thierry Lefevre, a post-doctoral fellow in de Roode's lab. "While the mother is expressing the behavior, only her offspring benefit. That finding is surprising for monarch butterflies".

The findings also may have implications for human health, says University of Michigan chemical ecologist Mark Hunter, who collaborated with de Roode's group on the research......... Posted by: Kelly      Read more         Source

October 8, 2010, 6:07 AM CT

Turtle, Dugongs 'at Risk Under Climate Change'

The "turtle and dugong capital of the world", the northern Great Barrier Reef (GBR) and Torres Strait region, faces increased pressure under climate change from human actions such as fishing, hunting, onshore development and pollution.

"Depletion of turtle and dugong numbers increases their vulnerability to other threats and lowers their ability to cope with climate change," Dr Mariana Fuentes of the ARC Centre of Excellence for Coral Reef Studies and James Cook University will tell the Coral Reef Symposium in Canberra today.

Dr Fuentes says that turtles in particular are vulnerable to the effects of climate change, which include decreases in hatching success, loss of nesting areas and overheated beaches, which will decrease the turtles' reproductive output and may significantly alter the sex ratio of their offspring.

Dr. Fuentes' research into the green, hawksbill and flatback turtles and well as dugongs in the northern GBR and Torres Strait is seeking to establish priorities for the management of marine megafauna to increase their resilience to climate change.

"Managers face the challenge of addressing the direct effects of climate change, as well as ongoing threats that dugongs and sea turtles face throughout their geographic range," she explains. "For logistical, financial and political reasons, managers cannot address all threats simultaneously, and so need to prioritize their actions......... Posted by: Kelly      Read more         Source

October 5, 2010, 7:30 AM CT

Powerful supercomputer peers into the origin of life

Supercomputer simulations at the Department of Energy's Oak Ridge National Laboratory are helping researchers unravel how nucleic acids could have contributed to the origins of life.

A research team led by Jeremy Smith, who directs ORNL's Center for Molecular Biophysics and holds a Governor's Chair at University of Tennessee, used molecular dynamics simulation to probe an organic chemical reaction that may have been important in the evolution of ribonucleic acids, or RNA, into early life forms.

Certain types of RNA called ribozymes are capable of both storing genetic information and catalyzing chemical reactions - two necessary features in the formation of life. The research team looked at a lab-grown ribozyme that catalyzes the Diels-Alder reaction, which has broad applications in organic chemistry.

"Life means making molecules that reproduce themselves, and it requires molecules and are sufficiently complex to do so," Smith said. "If a ribozyme like the Diels-Alderase is capable of doing organic chemistry to build up complex molecules, then potentially something like that could have been present to create the building blocks of life."

The research team found a theoretical explanation for why the Diels-Alder ribozyme needs magnesium to function. Computational models of the ribozyme's internal motions allowed the scientists to capture and understand the finer details of the fast-paced reaction. The static nature of conventional experimental techniques such as chemical probing and X-ray analysis had not been able to reveal the dynamics of the system......... Posted by: Kelly      Read more         Source

October 5, 2010, 7:28 AM CT

A decade of discovery for marine life

The Census of Marine Life, a ten-year initiative to describe the distribution and diversity of ocean life, draws to a close today with a celebration, symposium and press conference in London. At the press conference, researchers revealed the results of the census, including the discovery of new species, new patterns of biodiversity and more. Researchers at the University of Alaska Fairbanks have played a major role in what the census calls its "decade of discovery".

UAF researchers have led two multi-year projects as part of the census. Both projectsthe Arctic Ocean Diversity project and the Natural Geography in Shore Areas projectare dedicated to explaining the biodiversity of different areas in the world's ocean. Between them, the projects identified dozens of new species and cataloged nearshore organisms at more than 200 sites worldwide.

The Arctic Ocean Diversity project, also called ArcOD, is an international effort to identify the number and variety of marine creatures living in the Arctic. The project looks at organisms that live in arctic sea ice, the water column and on the seafloor, from microscopic plankton to fishes and birds.

Bodil Bluhm, associate professor of marine biology, Rolf Gradinger, associate professor of oceanography, and Russ Hopcroft, professor of oceanography, are leading the project......... Posted by: Kelly      Read more         Source

October 3, 2010, 9:09 PM CT

Ireland's smooth-hound sharks

They grow to over a meter in length, can weigh up to twelve kilos and each summer they swarm into the shallow waters of the Irish east coast. Despite this, the starry smooth-hound has remained Ireland's least well known shark species. However, thanks to scientists at University College Dublin, whose work is now reported in the Journal of Fish Biology, this appears to be about to change.

Dr. Edward Farrell, who recently graduated from UCD School of Biology & Environmental Science, spent the last four years studying these unusual sharks. Under the supervision of Dr. Stefano Mariani of the SBES and Dr. Maurice Clarke of the Marine Institute, the PhD project successfully investigated the age, growth, reproduction and identification of the species in the Northeast Atlantic.

"It's amazing how little was known about this species considering their size and abundance on the east coast," said Farrell. "Until recently we weren't even sure what species we were dealing with but we developed a genetic method which allowed us to confirm that it is the starry smooth-hound which occurs in Irish waters and not the related common smooth-hound. Once this was established we were able to investigate their life-history".

Starry smooth-hounds were previously considered to be a fast growing and early maturing species, meaning they were not a conservation concern. However the results of the four year project have revealed that starry smooth-hounds in Irish waters actually grow twice as slowly as previously estimated and only reproduce every two years rather than annually as is the case in the Mediterranean......... Posted by: Kelly      Read more         Source

September 25, 2010, 9:38 AM CT

Adapting to Darkness

University of Maryland biologists have identified how changes in both behavior and genetics led to the evolution of the Mexican blind cavefish (Astyanax mexicanus) from its sighted, surface-dwelling ancestor. In research reported in the August 12, 2010 online edition of the journal Current Biology, Professor William R. Jeffery, together with postdoctoral associates Masato Yoshizawa, and Špela Goricki, and Assistant Professor Daphne Soares in the Department of Biology, provide new information that shows how behavioral and genetic traits coevolved to compensate for the loss of vision in cavefish and to help them find food in darkness. This is the first time that a clear link has been identified between behavior, genetics, and evolution in Mexican blind cavefish, which are considered an excellent model for studying evolution.

Why Study Blind Cavefish.

Worldwide, about 80 different species of cave-dwelling fish have evolved from surface-dwelling fish, but in most cases the surface-dwelling ancestor has disappeared. "The Mexican blind cavefish is one of the only cases where a similar ancestor still exists," explains Professor Jeffery. "Except for the loss of eyes and pigment seen in the cave-dwelling form, the surface and cave-dwellers are hard to tell apart. You can study evolution very nicely if you have both the ancestral and derived forms of evolving animals."........ Posted by: Kelly      Read more         Source

September 25, 2010, 9:15 AM CT

Hidden insecticide resistance

A new technique pioneered at Liverpool School of Tropical Medicine (LSTM) is improving the detection and monitoring of insecticide resistance in field populations of an important malaria-carrying mosquito.

Scientists at LSTM, led by Dr Charles Wondji have developed a new technique which encourages the female Anopheles funestus mosquitoes to lay eggs which are then reared into adult mosquitoes to provide sufficient numbers to determine levels of insecticide resistance and to characterise the underlying mechanisms.

Explaining the significance, John Morgan, who designed the technique, said: "Malaria is the main cause of death in Uganda with some 12 million cases recorded annually. The Ministry of Health relies heavily on insecticide treated nets and spraying to control mosquitoes. The effectiveness of those control programmes depends on the ability to detect and monitor insecticide resistance.

"The An.funestus mosquito is difficult to collect and rear from the field and hence published studies of insecticide resistance in this species are limited. This new forced egg laying technique encourages the females to lay eggs which we were then able to rear into viable populations.

"This allowed us to study levels of resistance to particular insecticides and in doing so, we have been able to find the first documented resistance to pyrethroid/DDT insecticides in East Africa. This will enable scientists to map the distribution of this resistance and allow the Ministry of Health to modify its vector control programme, thereby increasing its effectiveness and helping to reduce the transmission of malaria"......... Posted by: Kelly      Read more         Source

September 23, 2010, 7:26 AM CT

China tops world fish

China leads the world in tonnage of fish caught annually as well as the amount of fish consumed, as per new findings reported in National Geographic magazine.

This research, which was conducted by the University of British Columbia in collaboration with the National Geographic Society and The Pew Charitable Trusts, ranks the top 20 nations that have the greatest impact on ocean ecosystems through catching or consuming marine wildlife.

China's top ranking results from its enormous population, despite its very low per capita footprint of fish catch and consumption. Japan is high on the list too, a result of its rate of consumption (often by importation) of fish rather than its catch. The "top 20" lists of fish catch and consumption are unveiled in the recent issue of National Geographic magazine.

The United States comes in third in both lists, due to its relatively large population and tendency to eat top predator fish such as Atlantic salmon. Peru ranks second in the world in catch though is not in the top 20 fish-consuming countries because Peruvians on the whole eat little seafood.

The data come from the SeafoodPrint study, led by Daniel Pauly of the University of British Columbia and National Geographic Ocean Fellow Enric Sala.

In assessing the true impact nations have on the seas, the team needed to look not just at what a given nation caught but also at what the citizens of that nation ate. Standard methods of measuring nations' impact on the sea are misleading because, as Pauly says, "every fish is different. A pound of tuna represents roughly a hundred times the footprint of a pound of sardines"......... Posted by: Kelly      Read more         Source

September 1, 2010, 7:11 AM CT

Free as a bird?

It may seem like birds have the freedom to fly wherever they like, but scientists at the University of Missouri have shown that what's on the ground has a great effect on where a bird flies. This information could be used by foresters and urban planners to improve bird habitats that would help maintain strong bird populations.

"Movement of individuals influences nearly every aspect of biology, from the existence of a single population to interactions within and among species," said Dylan Kesler, assistant professor in fisheries and wildlife at the University of Missouri's School of Natural Resources. "Movement determines where individual birds procreate. How they spread across the landscape affects who meets whom, which in turn dictates how genes are spread".

Kesler has observed that non-migrating resident birds tend to travel over forest "corridors," which are areas protected by trees and used by wildlife to travel. Birds choose to travel over forests because they can make an easier escape from predators as well as find food. Man-made features such as roads, as well as gaps forests from agriculture or rivers, can restrict birds to certain areas. When forests are removed, bird populations become isolated and disconnected, which can lead to inbreeding and weaker, more disease-prone birds......... Posted by: Kelly      Read more         Source

September 1, 2010, 7:08 AM CT

Effects of Sound on Marine Life

A combination of the biology of marine mammals, mechanical vibrations and acoustics has led to a breakthrough discovery allowing researchers to better understand the potential harmful effects of sound on marine mammals such as whales and dolphins.

An international team of scientists from San Diego State University, UC San Diego, and the Kolmården Zoo in Sweden has developed an approach that integrates advanced computing, X-ray Computerized axial tomography scanners, and modern computational methods that give a 3D simulated look inside the head of a Cuvier's beaked whale.

"Our numerical analysis software can be used to conduct basic research into the mechanism of sound production and hearing in these whales, simulate exposure at sound pressure levels that would be impossible on live animals, or assess various mitigation strategies," said Petr Krysl, a UC San Diego structural engineering professor who developed the computational methods for this research. "We think that our research can enable us to understand, and eventually reduce, the potential negative effects of high intensity sound on marine organisms."

The results of this research were recently published in a PLoS ONE article entitled, "A New Acoustic Portal into the Odontocete Ear and Vibrational Analysis of the Tympanoperiotic Complex" by Krysl, Ted W. Cranford, an adjunct professor of research in biology at San Diego State University; and Mats Amundin, a researcher at Sweden's Kolmården Zoo. Sponsors of the research include the office of the Chief of Naval Operations (CNO), Environmental Readiness Division......... Posted by: Kelly      Read more         Source