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, 9:50 PM CT

Farmers who plant after June 20

A costly deadline looms for a number of growers in the Midwest, as every day of waiting for the weather to cooperate to plant corn and soybeans reduces potential yields.

Illinois growers who plant corn or soybeans near the end of June can expect a 50 percent reduction in crop yield, as per a University of Illinois agriculture expert.

The US Department of Agriculture reports that corn and soybean growers in several Midwestern states are behind schedule on their planting. A cooler and wetter-than-average spring has left Illinois and Indiana furthest behind on planted corn and soybeans. Several other states are lagging behind their normal planting schedules, but by a lesser margin.

In Illinois, 95 percent of the corn is planted and 88 percent has emerged, but less than half of that is reported to be in good or excellent condition. Fully 14 percent of the acres planted are in poor or very poor condition, with another 38 percent reported as "fair." Those acres in poor or very poor condition may have to be replanted.

In Illinois, the corn was only seven inches high as of June 9, in comparison to an average 17 inches by this time in recent years.

"This has been a bad spring by most measures," said Illinois crop sciences professor Emerson Nafziger. "We keep seeing forecasts that look favorable and then that doesn't happen. The chance of having above-average yields has diminished greatly"......... Posted by: Erica      Read more         Source

June 10, 2008, 8:39 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

June 3, 2008, 10:34 PM CT

Willing To Pay A Premium For Locally Produced Food

New research suggests that the average supermarket shopper is willing to pay a premium price for locally produced foods, providing some farmers an attractive option to enter a niche market that could boost their revenues.

The study also showed that shoppers at farm markets are willing to pay almost twice as much extra as retail grocery shoppers for the same locally produced foods. Both kinds of shoppers also will pay more for guaranteed fresh produce and tend to favor buying food produced by small farms over what they perceive as corporate operations, as per the study.

"Our conclusion is that if a farmer wants to consider producing food for local distribution and marketing it locally, there are people who are willing to pay more for it," said Marvin Batte, a co-author of the study and the Fred N. VanBuren professor of agricultural, environmental and development economics at Ohio State University. "We are not saying that we should be producing all of our foods locally, just that this may be a viable, profitable activity for farmers".

And what's good for farmers also benefits consumers in this case, said Batte, director of the research project.

"This is an indication that certain groups out there value locally produced food and if farmers deliver that, it makes these consumers happier, so it's good for them, too," he said......... Posted by: Erica      Read more         Source

June 1, 2008, 10:30 PM CT

Genetic mutation linked to walking on all 4s

Barcelona, Spain: What are the genes implicated in upright walking of humans? The discovery of four families in which some members only walk on all fours (quadrupedality) may help us understand how humans, unlike other primates, are able to walk for long periods on only two legs, a scientist will tell the annual conference of the European Society of Human Genetics tomorrow (Monday 2 June).

The quadrupedal families in Turkey previously attracted attention in 2005, when they were discovered. Now the Turkish team reports that they have found the first gene implicated in quadrupedal locomotion in these families.

Professor Tayfun Ozcelik, of Bilkent University, Ankara, Turkey, and his colleagues, studied four unrelated families where some members were affected by the rare quadrupedic condition, Unertan syndrome, which is also linked to imperfect articulation of speech, mental retardation, and defects in the cerebellum, a part of the brain involved in motor control. They observed that the affected individuals in two families had mutations in the gene responsible for the expression of very low density lipoprotein receptor (VLDLR), a protein which is known to be critical to the proper functioning of the cerebellum during development.

Eventhough the families lived in isolated villages 200-300 km apart and reported no ancestral relationships, the researchers expected to find a single genetic mutation implicated in the condition. They were surprised to find that this was not the case......... Posted by: Janet      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