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

February 13, 2007, 9:13 PM CT

World shark attacks rise slightly

Shark attacks edged up slightly in 2006 but continued an overall long-term decline as overfishing and more cautious swimmers helped take a bite out of the aggressive encounters, new University of Florida research finds.

The total number of shark attacks worldwide increased from 61 in 2005 to 62 in 2006 and the number of fatalities remained stable at four, far below the 79 attacks and 11 fatalities recorded in 2000, said George Burgess, director of the International Shark Attack File housed at UF's Florida Museum of Natural History.

"This was a nice dull year and we love dull years because it means there are fewer serious attacks and fewer victims," Burgess said. "It's really quite remarkable when you have only four people a year die in the mouth of a shark and puts in perspective how small shark attack is as a phenomenon".

Fewer sharks are swarming near the shore where humans swim as larger numbers of shark and other fish of prey are killed each year, Burgess said. At the same time, a number of Third World countries are making strides in improving medical care and beach safety, while a number of people are getting smarter about where and when to get into the water, he said.

"They're starting to see that when they enter the sea, they're engaging in a wilderness experience as opposed to entering the equivalent of a backyard pool," he said......... Posted by: Kelly      Read more         Source

February 11, 2007, 8:48 PM CT

Wildlife Birth-control Method

Professor Cooper also raises concerns that individuals that survive the vaccine may be more likely to carry infectious diseases with the potential to affect other animals.

An immuno-contraceptive vaccine causes an animal's immune system to produce antibodies that act against some essential event or structure in the reproductive process. The antibodies can act against sperm, eggs or reproductive hormones, which prevent either fertilization or the production of sperm and ova.

Proponents of the technique, which was first tested nearly 20 years ago, regard it as more humane than the conventional methods of controlling wildlife populations, such as shooting, trapping, poisoning or viral diseases. It has drawn support from some politicians and animal-welfare agencies.

An expert in mammal reproduction, Professor Cooper, of the UNSW School of Biological, Earth and Environmental Sciences, questions immuno-contraception on three grounds.

"Firstly, immuno-contraceptives are ineffective against substantial minorities of animals, probably for genetic reasons," Professor Cooper says. "If so, the genes responsible for this lack of response will be passed on to offspring. Within a few generations most of the population will be unresponsive to the immunocontraceptive, so its effectiveness as a form of birth control is likely to be short-lived".........

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February 8, 2007, 10:03 PM CT

Animal Studies In The Land Of The Midnight Sun

The temperature hovers around freezing, but the sun is up for 24 hours each day. How do animals living in the continuous light of the Arctic summer know when to sleep and when to be active? Do they maintain a 24-hour cycle of rest and activity, or does living in continuous light alter their circadian rhythm?

Answering these questions may improve our understanding of biological clocks -- the internal, genetically programmed cycle of rest and activity that affects the behavior, metabolism and physiology of all animals, including humans. A better understanding may also help solve problems -- such as shift-work fatigue, jet lag and even seasonal affective disorder -- that are linked to disruptions of biological clocks.

One scientist who has spent a lifetime pursuing these questions and finding answers that have helped build the field of biological clock research is G. Edgar Folk, Ph.D., emeritus professor of molecular physiology and biophysics at the University of Iowa Roy J. and Lucille A. Carver College of Medicine.

Folk notes that humans have a natural circadian rhythm of close to, but not exactly, 24 hours. Importantly, all biological clocks are adjustable and respond to environmental cues such as sunrise or sunset, which continuously reset the clock and keep us on a regular 24-hour schedule.........

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February 8, 2007, 9:20 PM CT

Male-killing Bacteria and Butterflies

A study at UCL (University College London) finds that a high-prevalence of male-killing bacteria active in a number of species of insect including the butterfly, actually increases female promiscuity and male fatigue.

The team observed that when the male insect population drops -- killed off by the bacteria -- the female butterfly becomes more sexually rampant. Males conversely show signs of fatigue and put less effort into mating.

In some populations of tropical butterfly the entire mating system is determined by a group of bacteria known as Wolbachia, as per the study, reported in the journal 'Current Biology'.

Dr Sylvain Charlat, of the UCL Department of Biology, who led the study, said: "Male-killling bacteria are found in a number of insect species including the British ladybird. We wanted to know what the effect of the bacteria is on the mating system, and here we've shown that butterfly mating patterns are strongly determined by the killer bacteria.

"Contrary to expectation, we also find that female promiscuity actually rises when male numbers are reduced. Greater numbers of female partners leads to fatigue in males. They start producing smaller sperm packages. Unfortunately, the female butterflies instinctively know that the packages are smaller and that their chances of having been impregnated after mating are lower than usual. This just makes them more rampant!".........

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February 7, 2007, 9:35 PM CT

Horse genome assembled

The first draft of the horse genome sequence has been deposited in public databases and is freely available for use by biomedical and veterinary researchers around the globe, leaders of the international Horse Genome Sequencing Project announced today.

The $15 million effort to sequence the approximately 2.7 billion DNA base pairs in the genome of the horse (Equus caballus) was funded by the National Human Genome Research Institute (NHGRI), one of the National Institutes of Health (NIH). A team led by Kerstin Lindblad-Toh, Ph.D., at the Eli and Edythe L. Broad Institute of the Massachusetts Institute of Technology and Harvard University, in Cambridge, Mass., carried out the sequencing and assembly of the horse genome.

Approximately 300,000 Bacterial Artificial Chromosome (BAC) end sequences, which provide continuity when assembling a large genome sequence, were contributed to the horse sequencing project by Ottmar Distl, D.V.M., Ph.D. and Tosso Leeb, Ph.D., from the University of Veterinary Medicine, in Hanover, Germany and Helmut Blöcker, Ph.D., from the Helmholtz Centre for Infection Research in Braunschweig, Germany. Production of the BAC end sequences was funded by the Volkswagen Foundation and the State of Lower Saxony.

Sequencing of the domestic horse genome began in 2006, building upon a 10-year collaborative effort among an international group of scientists to use genomics to address important health issues for equines, known as the Horse Genome Project (www.uky.edu/Ag/Horsemap/). The horse whose DNA was used in the sequencing effort is a Thoroughbred mare named Twilight from Cornell University in Ithaca, N.Y. Researchers obtained the DNA from a small sample of the animal's blood. To download a high-resolution photo of Twilight, go to http://www.genome.gov/pressDisplay.cfm?photoID=20008. Twilight is stabled at the McConville Barn, Baker Institute for Animal Health, College of Veterinary Medicine, at Cornell University, with a small herd of horses that have been selected and bred for more than 25 years to study the mechanisms that prevent maternal immunological recognition and destruction of the developing fetus during mammalian pregnancy. The research, conducted by Cornell professor Doug Antczak, V.M.D, Ph.D., and funded by the National Institute of Child Health and Human Development, has implications in reproduction, clinical organ transplantation and immune regulation. ........

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February 6, 2007, 9:44 PM CT

Toads with a Task

The strings of sticky eggs laid at the Central Park Zoo were bound for great things, and sun-splashed places. As part of a program to revitalize the endangered Puerto Rican crested toad, animal husbandry experts from the Wildlife Conservation Society (WCS) reared more than 450 healthy tadpoles in New York and released them in a manmade pond in the island's Guanica State Forest. It is hoped that the tadpoles will someday return to these same wetlands as warty, golden-eyed adult toads to lay eggs of their own.

Bruce Foster, Collections Manager for the Central Park Zoo, stowed his precious cargo in plastic bags of water and pure oxygen before he escorted them down to the release site in Puerto Rico. There he met with other participants in the ongoing reintroduction effort, including the Fort Worth Zoo. The Buffalo Zoo and Sedgwick County Zoo also sent down shipments of pollywogs, contributing to a total of 2,700 tadpoles for the release. The group is part of the Puerto Rican Crested Toad Species Survival Plan (SSP), a project founded in 1984 under the auspices of the Association of Zoos and Aquariums. In addition to boosting the long struggling toad population itself, the SSP aims to raise awareness of the species' plight through island-wide public education and outreach programs. The U.S. Fish and Wildlife Service and the Puerto Rican Department of Natural Resources are also supporting.........

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February 5, 2007, 9:13 PM CT

Mule Deer - Odocoileus hemionus

The forested area of Wind Cave National Park includes scattered groves of ponderosa pine trees with a few hardwoods and one large forested area occupying the western and northwestern sections of the park. Small mammals like the red squirrel, porcupine, and chipmunk are often seen in these areas along with larger mammals like the mule deer and the elk.

The mule deer, while closely correlation to the eastern species-the white-tailed deer, are remarkably distinct in their biological, ecological, and behavioral attributes. The mule deer evolved in the dry, rugged badlands and mountains of the west. They have a distinctly different gait from the leisurely, graceful leaps of the white-tail. When startled, a mule deer will move in a series of stiff-legged jumps with all four feet hitting the ground together. This gait offers two advantages: it allows the deer to out-distance predators in rough terrain, and to see above the thick brush. If necessary, they can turn or completely reverse direction in the course of a single bound.

Other characteristics that distinguish mule deer are the large size of their ears (for which they were named), their overall shape and large size, the form of the antlers and the tail. The mule deer carries its thin, black-tipped tail drooped, unlike the uplifted, bushy white tail of its cousin.........

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February 5, 2007, 6:41 PM CT

Keeing Fish Out Of Hot Water

Right now some tubeworm tartare and clams on the half shell would really hit the spot, so you're headed for the all-night caf.

"All-night" being the operative word because the volcanic ridge you're tooling along is nearly 1.5 miles below the surface. The term "where the sun don't shine" perfectly describes the place. It's pitch black.

Darn, but what's that loud rumbling up ahead?

Must be one of those pesky black smokers. Some of those babies can fry your face off. A detour is highly indicated.

The long-held assumption that black smokers are silent is wrong, as per recently published research led by Timothy Crone, a University of Washington doctoral student in oceanography. It's prompting researchers to wonder: Could the sound and vibrations of black smokers be the reason fish in total darkness avoid being poached by waters as hot as 750 F? And might similar sounds guide them to the smorgasbord of tube worms, mussels, shrimp, snails and other fauna at vents with more temperate waters?

Want to be the first on your block to hear what a black smoker sounds like?

The research was reported online during the inaugural month of the Public Library of Sciences' interactive journal, PLoS ONE. Aimed at involving more people in science, published results are available without a subscription and can include a wealth of audio, video and other materials.........

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February 2, 2007, 4:37 AM CT

Algae Toxin And The Fish-kill Mystery

A team of scientists from the Hollings Marine Laboratory in Charleston, S.C., has uncovered a subtle chemical pathway by which normally inoffensive algae, Pfiesteria piscicida, can suddenly start producing a lethal toxin. The discovery, reported last week in Environmental Science and Technology,* could resolve a long-standing mystery surrounding occasional mass fish kills on the East Coast.

Pfiesteria has been implicated for years in a series of otherwise unexplained episodes of mass fish death throughout its range from roughly Delaware to Alabama, especially in the Neuse River in North Carolina and the Chesapeake Bay. The single-cell organism can experience explosive growth resulting in algae blooms in coastal waters. While it has been suspected not only in fish kills but in incidents of human memory loss and other environmental and health-related effects, no one has ever conclusively identified the actual mechanism. Attempts to grow lethal Pfiesteria in the laboratory have had inconsistent results.

The Hollings Marine Laboratory is a joint institution of the National Oceanic and Atmospheric Administration (NOAA), the National Institute of Standards and Technology (NIST), the South Carolina Department of Natural Resources, the College of Charleston, and the Medical University of South Carolina (MUSC). Lead researcher Peter Moeller of NOAA suspected that the presence or absence of heavy metals might be the missing factor accounting for Pfiesteria's lethality, and put together a multidisciplinary research team to identify the actual toxin and the conditions under which it is produced.........

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