June 23, 2008, 7:43 PM CT

Single Insecticide Application Can Kill 3 Cockroach Generations

One dose of an insecticide can kill three generations of cockroaches as they feed off of each other and transfer the poison, as per Purdue University entomologists who tested the effectiveness of a specific gel bait.

It is the first time that researchers have shown that a pest control bait will remain effective when it's transferred twice after the first killing dose, said Grzegorz "Grzesiek" Buczkowski, assistant professor of entomology. Passing the insecticide from one cockroach to the next is called horizontal transfer.

"Our findings are exciting because cockroaches are difficult to control since they multiply so rapidly," Buczkowski said. "They are particularly bad in urban housing, and they can cause health problems".

It's difficult to find and rid areas of the insects because cockroaches come out at night and live in inaccessible places, he said. They invade places where they easily can find plenty of food and water. In addition, cockroaches are attracted to where other cockroaches are by a chemical compound, called pheromones, that animals secrete and which influences other cockroaches' behavior.

In a laboratory study, the researchers used German cockroaches, the most common household species in the United States, to test a DuPont product with the active ingredient indoxacarb. Eventhough the scientists only studied indoxacarb, Buczkowski said it's possible other insecticides also may have three-generation horizontal transfer kill capabilities......... Posted by: Kelly      Read more         Source

June 18, 2008, 8:33 PM CT

High hormone levels in seabird chicks prepare them to kill their siblings

The Nazca booby, a Galpagos Island seabird, emerges from its shell ready to kill its brother or sister. Wake Forest University biologists and their colleagues have linked the murderous behavior to high levels of testosterone and other male hormones found in the hatchlings.

The study appears in the June 18 edition of the online journal PLoS ONE available at http://www.plosone.org/doi/pone.002460.

The elevated levels of male hormones, called androgens, increase aggression in both male and female chicks and prepare the birds to fight to the death as soon as they hatch, said David J. Anderson, professor of biology at Wake Forest and project leader.

Much of the field work was completed by Martina Mller, while she was a graduate student at Wake Forest.

"The older of two Nazca booby hatchlings unconditionally attacks and ejects the younger from the nest within days of hatching," Anderson said. Because Nazca boobies have difficulty raising more than one chick, it is important for the older chick to vanquish the younger one in order to increase its own chances of survival.

As per the study, the high hormone levels also cause the surviving chicks to behave like bullies after they grow up. They frequently seek out nestlings in their colony, and during those visits they often bite and push around the defenseless youngsters......... Posted by: Kelly      Read more         Source

June 17, 2008, 10:01 PM CT

First successful reverse vasectomy on Przewalski's horse

Veterinarians at the Smithsonian's National Zoo have performed the first successful reverse vasectomy on a Przewalski's horse (E. ferus przewalskii; E. caballus przewalskii classification debated), pronounced zshah-VAL-skeez. Przewalksi's horses are a horse species native to China and Mongolia that was declared extinct in the wild in 1970. Currently, there are approximately 1500 of these animals maintained at zoological institutions throughout the world and in several small reintroduced populations in Asia. This is the first procedure of its kind to be performed on an endangered equid species.

The genes of Minnesotathe horse who underwent the surgeryare extremely valuable to the captive population of the species, which researchers manage through carefully planned pairings to ensure the most genetically diverse population possible. The horse was vasectomized in 1999 at a prior institution so that he could be kept with female horses without reproducing. He came to the National Zoo in 2006.

While surveying the captive North American population of Przewalski's horses, researchers realized Minnesota's genetic value. Based on his ancestry, he is the seventh most genetically valuable horse in the North American breeding program. Zoo researchers were confident that if they could successfully reverse the vasectomy, Minnesota would be able to sire a foal through natural mating......... Posted by: Kelly      Read more         Source

June 10, 2008, 8:38 PM CT

Study of guanacos launched in Chile

The Wildlife Conservation Society has launched a study in Chile's Karukinka reserve on Tierra del Fuego to help protect the guanaco a wild cousin of the llama that once roamed in vast herds from the Andean Plateau to the steppes of Patagonia.

Today, the guanaco population has dwindled to perhaps half a million animals that live in highly fragmented populations due to habitat loss and competition from livestock. Tierra del Fuego, particularly Karukinka, holds the largest wild population of Chilean guanacos. The WCS study of these poorly understood members of the camel family will provide critical data to help restore one of the most endangered natural phenomena in Latin America the overland migration of guanacos a critical element to understanding biodiversity of the area.

Donated to WCS by Goldman Sachs in 2004, Karukinka consists of 740,000 acres of wilderness, including the world's southernmost old-growth forest as well as extensive peat bogs, unique river systems, and grasslands. Goldman Sachs has provided key funding for this guanaco study.

"This study is pivotal in understanding the ecological importance of the guanaco and ultimately conserving them as a species," said Dr. Steven E. Sanderson, President and CEO of the Wildlife Conservation Society. "Historically, guanacos played a similar ecological role in Latin America as did bison in North America, with vast herds wandering over large landscapes. We commend Goldman Sachs for their support to help protect an iconic species that is so important to Tierra del Fuego's natural heritage"......... Posted by: Kelly      Read more         Source

June 9, 2008, 9:11 PM CT

Man-made Chemical Pollutants Found in Deep-sea Octopods and Squids

New evidence that chemical contaminants are finding their way into the deep-sea food web has been found in deep-sea squids and octopods, including the strange-looking "vampire squid". These species are food for deep-diving toothed whales and other predators.

In a study would be reported in the journal Marine Pollution Bulletin, Michael Vecchione of NOAA Fisheries' National Systematics Laboratory and his colleagues Michael Unger, Ellen Harvey and George Vadas at the Virginia Institute of Marine Science of The College of William and Mary report finding a variety of chemical contaminants in nine species of cephalopods, a class of organisms that includes octopods, squids, cuttlefishes and nautiluses.

"It was surprising to find measurable and sometimes high amounts of toxic pollutants in such a deep and remote environment," Vecchione said. Among the chemicals detected were tributyltin (TBT), polychlorinated biphenyls (PCBs), brominated diphenyl ethers (BDEs), and dichlorodiphenyl-trichloroethane (DDT). They are known according tosistent organic pollutants (POPs) because they don't degrade and persist in the environment for a very long time.

Cephalopods are important to the diet of cetaceans, a class of marine mammals which includes whales, dolphins and porpoises. Cephalopods are the primary food for 28 species of odontocetes, the sub-order of cetaceans that have teeth and include beaked, sperm, killer and beluga whales and narwhals as well as dolphins and porpoises......... Posted by: Kelly      Read more         Source

June 8, 2008, 9:12 PM CT

Diet prior to pregnancy determines sheep's gender

Maternal diet influences the chances of having male or female offspring. Research published recently in BioMed Central's open access journal Reproductive Biology and Endocrinology has demonstrated that ewes fed a diet enriched with polyunsaturated fats for one month previous to conception have a significantly higher chance of giving birth to male offspring.

This study was carried out by a team of scientists from the Division of Animal Sciences at the University of Missouri and led by R Michael Roberts. Roberts explains how diet at the time of conception is the most important factor when it comes to influencing the sex of the offspring "Our study ruled out body condition, ewe weight, prior births, time of breeding, and likely dominance as reasons for the gender skewing. Rather, it was the composition of the diet consumed in the time period around conception that was responsible for this sex-ratio effect".

Polyunsaturated fats are essential nutrients. It is believed that the dietary ratio between omega-3 and omega-6 fats has important biological effects, particularly in terms of inflammation, immunity and central nervous system signalling. The omega-6 fats used in this study were protected from digestion by naturally occurring rumen bacteria to ensure that they would be absorbed through the intestines of the sheep......... Posted by: Kelly      Read more         Source

June 5, 2008, 5:50 PM CT

Winnie the whimbrel flies 3,200 miles in 146 hours

Scientists from the College of William and Mary's Center for Conservation Biology and The Nature Conservancy have observed the record-setting migration of a shorebird from feeding grounds on the Delmarva Peninsula to breeding grounds on the McKenzie River near the Alaska-Canada border.

The bird's six-day flight is challenging conventional scientific thinking about long-distance migration routes and underscores the ecological importance of areas of the Delmarva Peninsula, which includes the state of Delaware and the Eastern Shore of Maryland and Virginia.

The bird, a female whimbrel known as Winnie, was fitted with a state-of-the-art satellite tracking device weighing just over a third of an ounce, as per Bryan Watts, director of the Center for Conservation Biology. Winnie left the study area on May 23, flying northwest at an average flight speed of nearly 22 miles per hour, covering more than 5,000 kilometers (3,200 miles) in no more than 146 hours.

"This discovery sets a new distance record in the flight range of this species and highlights the hemispheric importance of the Delmarva Peninsula as a staging area for migratory shorebirds," Watts said. "The flight documented this spring challenges some long-held assumptions and raises several new questions about whimbrel ecology"......... Posted by: Kelly      Read more         Source

May 28, 2008, 6:12 PM CT

The case of the disappearing species

Throughout the overlooked depths of Lake Michigan and other Great Lakes, a small but important animal is rapidly disappearing.

Until recently, the animal - a shrimplike, energy-dense creature called Diporeia - was a major food source for commercially important species like lake whitefish and a number of prey fish upon which salmon, trout and walleye rely.

Researchers are employing new research methods in a quest to explain their population freefall, which threatens to negatively affect the Lakes' ecosystems and $4 billion sport fishing industry, said Purdue University researcher Marisol Sepúlveda.

"We want to narrow down likely causes for this decline," said Sepúlveda, an assistant professor of forestry and natural resources. "It may help us halt the animal's further disappearance".

Sepúlveda has begun to identify substances involved in Diporeia metabolism, the set of chemical reactions that maintain life and allow organisms to respond to stress. Differences in levels of these metabolites between individuals and populations in various regions of the lakes may point toward the stressor or stressors responsible for their decline, she said.

In the same biological class as krill and shrimp, these rice grain-sized crustaceans dwell on lake bottoms and feed on descending algal plankton. Their bodies contain 30 percent to 40 percent lipids like fats and oils, making them a vital energy and nutrient source for the entire food web......... Posted by: Kelly      Read more         Source

May 27, 2008, 10:09 PM CT

Healthy Parents Provide Clues to Survival of Young Haddock

In 2003, haddock on Georges Bank experienced the largest baby boom ever documented for the stock, with an estimated 800 million new young fish entering the population. With typical annual averages of 50 to 100 million new fish in the last few decades, fisheries biologists have been puzzled by the huge increase and its ramifications for stock management. They have been looking for answers and may have found one - healthy adults.

In a study would be reported in the recent issue of the Canadian Journal of Fisheries and Aquatic Sciences, Dr. Kevin Friedland and his colleagues from NOAA's National Marine Fisheries Service and the University of Massachusetts suggest that the successful 2003 recruitment year is correlation to the fall phytoplankton bloom the year before spawning, and to the condition of the adult haddock. Phytoplankton, microscopic marine plants, form the basis of the ocean food web, and are the main source of food for a number of fish and other animals in the ocean. The fall 2002 bloom was significant, providing a larger than usual source of food for the ecosystem.

"Simply put, having more food to eat gives adult haddock a chance to get into better physical shape to reproduce healthy offspring with a higher chance of survival," says Friedland, a research scientist at NOAA Fisheries' Northeast Fisheries Science Center. "We evaluated the usually applied factors that control recruitment, and observed that the fall phytoplankton bloom the year before seems to link parental condition with a good recruitment. We call this new approach the parental condition hypothesis"......... Posted by: Kelly      Read more         Source

May 27, 2008, 9:34 PM CT

The secret behind silkworm's hardy stomachs

Silkworms have a unique ability to eat toxic mulberry leaves without feeling ill, and scientists have come one step closer to understanding why: silkworms contain a special digestive enzyme that is not affected by mulberrys toxic chemicals.

Mulberry leaves contain an extremely high amount of alkaloids that inhibit enzymes that break down sucrose (sugar), and thus are potentially quite toxic. However, one type of sucrase called beta-fructofuranosidase is not affected by these alkaloids.

Until now, this enzyme has not been found in any animals, but Toru Shimada and his colleagues believed this might explain the silkworms unique diet.

The scientists scanned the silkworm genome and discovered two fructofuranosidase genes, eventhough only one was actually expressed in the worm. This gene (BmSuc1) was, as expected, concentrated in the worms gut, eventhough surprisingly was also prevalent in the silk gland. When they isolated the enzyme from silkworms, the scientists found it could effectively digest sucrose.

Shimada and his colleagues note that further work is needed to determine if this special enzyme is the sole reason for silkworms resistance to mulberry toxins. Its possible that fructofuranosidases may turn up in other insects that cannot eat mulberry leaves, indicating additional factors are at work......... Posted by: Kelly      Read more         Source