February 26, 2007, 6:21 PM CT

A cockroach mom shelters her newborn

One of the defining differences between the sexes is in the size of their gametes. Males make a number of tiny sperm while females make only a few large eggs. This suggests that sperm are cheap while eggs are expensive. Yet sperm can be very long lived, while eggs degenerate quickly after they are made if they are not fertilized. Why don't females take better care of their expensive eggs? After all, if the females don't use their eggs they have fewer offspring, whereas males make more sperm then they will use anyway. This evolutionary conundrum there should be selection for females to keep their eggs fresh until they are used has recently been studied by Dr. Trish Moore and her colleagues at the Cornwall Campus of the University of Exeter, with support from NERC, and is reported in the recent issue of The American Naturalist.

Moore and his colleagues examined why females don't keep their eggs fresh in a cockroach where females mate only once during a reproductive cycle, give live birth, and therefore are choosy about the male with which they will mate. Females can't be too choosy, however. If they wait too long to mate they lose good quality oocytes through programmed cell death. But Moore's team finds that some females have genes that would allow them to maintain eggs even if they delay mating. So why aren't all females delaying cell death and holding onto their eggs? Moore speculates that perhaps these genes play a dual role and while they may be beneficial under one environment, when females don't mate, they might be harmful under another, such as when food is limiting. "When females are starving, hanging on to yolky eggs full of nutrients is bad. Instead a female could recycle those nutrients into her survival. So females face a decision between keeping eggs fresh for producing offspring now, or using those nutrients herself and taking the chance she can reproduce later." The group is currently investigating this trade-off arising from a conflict over food or sex. Eventhough this is a new twist in the conflict over food or sex, the result is a familiar one in evolutionary biology; it is hard to be best at everything......... Posted by: Kelly      Read more         Source

February 22, 2007, 10:18 PM CT

Warming Climate, Cod Collapse

Ecosystems along the continental shelf waters of the Northwest Atlantic Ocean, from the Labrador Sea south of Greenland all the way to North Carolina, are experiencing large, rapid changes, reports a Cornell oceanographer in the Feb. 23 issue of Science.

While some researchers have pointed to the decline of cod from overfishing as the main reason for the shifting ecosystems, the article emphasizes that climate changes are also playing a big role.

"It is becoming increasingly clear that Northwest Atlantic shelf ecosystems are being tested by climate forcing from the bottom up and overfishing from the top down," said Charles Greene, director of the Ocean Resources and Ecosystems Program in Cornell's Department of Earth and Atmospheric Sciences. "Predicting the fate of these ecosystems will be one of oceanography's grand challenges for the 21st century".

Most researchers believe the planet is being warmed by greenhouse gases emitted in the burning of fossil fuels, and by changing land surfaces. Early signs of this warming have appeared in the Arctic: Since the late 1980s, researchers have noticed that pulses of fresh water from increased precipitation and melting of ice on land and sea in the Arctic have flowed into the North Atlantic Ocean and made the water less salty......... Posted by: Kelly      Read more         Source

February 21, 2007, 9:41 PM CT

Influenza Virus Genomes Now Accessible

The Influenza Genome Sequencing Project, funded by the National Institute of Allergy and Infectious Diseases (NIAID), one of the National Institutes of Health (NIH), announced recently that it has achieved a major milestone. The entire genetic blueprints of more than 2,000 human and avian influenza viruses taken from samples around the world have been completed and the sequence data made available in a public database.

"This information will help researchers understand how influenza viruses evolve and spread," says NIH Director Elias A. Zerhouni, M.D., "and it will aid in the development of new flu vaccines, therapies and diagnostics".

"Researchers around the world can use the sequence data to compare different strains of the virus, identify the genetic factors that determine their virulence, and look for new therapeutic, vaccine and diagnostic targets," says NIAID Director Anthony S. Fauci, M.D.

The Influenza Genome Sequencing Project, initiated in 2004, has been carried out at the NIAID-funded Microbial Sequencing Center managed by The Institute for Genomic Research (TIGR) of Rockville, Maryland. The project is currently directed by David Spiro, Ph.D., and Claire Fraser, Ph.D., at TIGR and Elodie Ghedin, Ph.D., at the University of Pittsburgh School of Medicine. Recently, growing sequencing capacity has enabled the production rate to increase to more than 200 viral genomes per month. Eclipsing todays milestone of 2,000 genomes, the microbial sequencing center will continue to rapidly sequence more influenza strains and isolates and will make all the sequence data freely available to the scientific community and the public through GenBank, an Internet-accessible database of genetic sequences maintained by the National Center for Biotechnology Information (NCBI) at NIHs National Library of Medicine, another major contributor to the project......... Posted by: Janet      Read more         Source

February 21, 2007, 9:30 PM CT

Disappearing, Wild Elk Return to Ontario

After disappearing from Ontario due to over hunting in the 19th century, wild elk have returned to the province thanks to the efforts of the Ontario elk restoration program. According to a report on the program's success, published in the recent issue of Restoration Ecology, 460 elk were brought from Alberta and released in various Ontario sites between 1998 and 2001.

"The Ontario elk restoration program has met with great success primarily due to the collaborative, multi-partnered approach to wildlife management," says Dr. Rick Rosatte, author of the report and senior research scientist with the Ontario Ministry of Natural Resources. Although the transferred elk experienced a 41 percent mortality rate between 1998-2004, the majority of surviving elk were able to reproduce. According to the program's 2004 data, 375 to 440 elk are currently living in Ontario.

Dr. Rosatte is quick to point out that the program faced many challenges. Many of the reintroduced elk did not survive long after being transferred, particularly due to wolf predation, illegal hunting and stress from the transfer process. However, the death rate is decreasing each year, suggesting that the animals are adapting to their new home.

Although pleased with the program's success to date, Rosatte asserts that the work is far from over. "Our challenge for the future will be to develop accurate methods to estimate elk numbers and locations, so that elk can be managed in a sustainable manner, and in a way that minimizes conflicts between elk and humans"......... Posted by: Kelly      Read more         Source

February 21, 2007, 9:06 PM CT

Lizards 'shout' Against A Noisy Background

Lizards that signal to rivals with a visual display "shout" to get their point across, UC Davis scientists have found.

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 observed 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 especially 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......... Posted by: Kelly      Read more         Source

February 21, 2007, 5:03 AM CT

New Bird, Bat Species From Extensive DNA Barcode Studies

At unprecedented levels of difficulty involving highly biodiverse and continent-sized landscapes, researchers have successfully tested their ability to identify and DNA "barcode" entire assemblages of species -- the prelude to a genetic portrait of all animal life on Earth.

Revealing their results in the UK journal Molecular Ecology Notes, they report having assembled a genetic portrait of birdlife in the U.S. and Canada, and announce the startling discovery of 15 new genetically distinct species, nearly indistinguishable to human eyes and ears and consequently overlooked in centuries of bird studies.

The barcoders also successfully logged the DNA attributes of 87 bat species of Guyana and reveal six new species, characterized by unique genetic make-up. One of the new species, a look-alike of Trachops cirrhosus, feasts on frogs.

As well, the researchers report that 14 pairs of North American bird species with separate identities are in fact DNA twins, two trios of bird species are DNA triplets, and no less than eight gull species are virtually DNA identical.

The complementary papers describing the bird and bat initiatives were authored by scientists from Guelph, Ottawa and Toronto, Canada, and from New York City and Washington D.C., USA......... Posted by: Kelly      Read more         Source

February 21, 2007, 4:59 AM CT

Link Between Food Odors And Lifespan In Fruit Flies

Scientists hoping to learn why organisms tend to live longer if their intake of calories is restricted have made a startling discovery - in fruit flies, just the smell of food can have a negative effect on longevity.

Researchers have known for decades that restricted dietary intake can increase the lifespan of a number of species, but the mechanism that causes this is not understood. Short-lived organisms like the fruit fly, Drosophila melanogaster, are studied to help unravel this mystery, and the knowledge gained could have important implications for human health.

In a paper would be published in Science, the journal of the American Association for the Advancement of Science, a group of scientists from Baylor College of Medicine in Houston, New Mexico State University in Las Cruces and the University of Houston report that exposure to food odors can modulate lifespan and partially reverse the longevity-extending effects of dietary restriction in fruit flies.

"Not only can they not have their cake - they can't smell their cake" without shortening their lifespans, said Wayne Van Voorhees, a faculty member in the Molecular Biology Program at New Mexico State University and a member of the research collaboration.

The researchers, led by Scott Pletcher of the Huffington Center on Aging at Baylor, measured the lifespans of different strains of fruit flies in the presence and absence of food odors - specifically live yeast, which is an important component of the flies' diets. Exposure to food odors reduced lifespan in flies that had been subjected to dietary restriction. The reductions ranged from 6 percent to 18 percent - not as much reduction as actual consumption of more food caused, but significant enough to show that food odors have a modulating effect on lifespan......... Posted by: Kelly      Read more         Source

February 20, 2007, 7:27 PM CT

Protein key to organ growth

hen amounts of a small protein called TCTP (translationally controlled tumor protein) are reduced in the cells of fruit flies, they are smaller than normal, indicating that the protein plays a major role in the growth and proliferation of cells, said scientists at Baylor College of Medicine in a report in current issue of the journal Nature.

Work in his laboratory shows that TCTP plays a role in regulating Rheb (Ras homologue enriched in brain), a protein controlling growth and differentiation, and may give clues to therapy of a particular non-malignant disease called tuberous sclerosis that is linked to the control exerted through the same pathway, said Dr. Kwang-Wook Choi, associate professor of molecular and cellular biology at BCM and colleagues.

When flies completely lack the protein, they do not live very long. However, when flies have only a little TCTP in their cells, they are very small, said Choi. Graduate student Ya-Chieh Hsu, through a series of studies that concentrated on the effect of the protein on the eyes and wings, elucidated the role of TCTP in the cell.

"She was able to show genetically and biochemically that TCTP is directly involved in regulating Rheb function so that it regulates cell size as well as cell numbers. We observed that in the case of dysfunction, the eyes and wings get smaller," said Choi. "If you completely knock out this function in the eye, they have no eyes"......... Posted by: Janet      Read more         Source

February 15, 2007, 6:24 AM CT

Grizzly Bears Feast On Diverse Diet

Theres no such thing as picky grizzly bearstheyll eat almost anything they can find. A new University of Alberta study that tracked food habits of the Alberta grizzly bear living in the foothills sheds some light on the animals varied diet and their activity pattern.

Alberta bears have remarkably diverse diets, said Dr. Mark Boyce, biological sciences professor at the U of A and co-author on the study. Theyll eat just about anything.

Ants, fruits, moose and plants are a few staples of the Alberta grizzly bears diet. This new research study was the most comprehensive examination of grizzly bear foods ever conducted in Canada. Using global positioning system (GPS) radiotelemetry technology and analyzing 665 feces collected from 18 grizzly bears over a period of three years, the researchers observed that the bears packed a lot of activity into 24 hours. The research was recently reported in the Journal of Mammalogy.

Much is known about what bears in mountainous areas eat but little is known of the diets of grizzly bears living in boreal forests also used by humans. As well, this new research looked at five different activities the bears use to find foodwhether it feeds on flowers, insects, fruits, digs for plants or kills other animals, specifically ungulates......... Posted by: Kelly      Read more         Source

February 13, 2007, 9:43 PM CT

Is there a pilot in the insect?

When they fly, insects use their vision for piloting, just like human pilots. The electric signals from their facetted eyes travel through specialized neurons to stimulate the wing muscles, which let the insects correct their flight and avoid crashes. Could these same neurons be used in a sort of "automatic pilot"? This is what Nicolas Franceschini, Franck Ruffier and Julien Serres have just shown. These biorobotics specialists from the Movement and Perception Laboratory (CNRS/Universit de la Mditerrane) in Marseille, France have revealed an automatic mechanism called the "optic flow regulator" that controls the lift force. The scientists obtained these results by modeling the overland flight navigation of insects using experiments carried out on OCTAVE, a captive flying robot microhelicopter that can reproduce much of the mysterious natural insect behavior. Their work is published online in Current Biology, February 8, 2007.

How does a tiny creature like a fly or a bee, with a brain the size of a pinhead, manage to make such a magnificent job of controlling its flight, and avoid crashing to the ground? Today it is known that the sensory motor prowess of these flying miniatures depends on the nervous system, made up of between one hundred thousand and one million neurons. When an insect, bird or pilot flies over land, the image of the ground below sweeps from front to back across the central part of the visual field, creating an "optic flow", which is defined as the angular speed at which the ground contrasts move past. By definition, this angular speed is equal to the ratio of the horizontal speed and the altitude. What these authors call an "optic flow regulator" is a reflex that keeps the optic flow, and thus the speed/altitude ratio, at a constant value. If the insect changes speed, this reflex will make it change altitude so that ratio remains constant. Adjusting the speed/altitude ratio means that the insect has no need to measure either its speed or its altitude......... Posted by: Kelly      Read more         Source