September 25, 2006, 9:22 PM CT

Polar Bear Habitat Preferences

The Wildlife Society's 13th Annual Conference and Trade Show is being held September 23-27, 2006 in downtown Anchorage, Alaska at the William A. Egan Civic and Convention Center.

Polar bear habitat preferences and prey availability in a changing sea ice environment. In the Beaufort Sea, polar bears (Ursus maritimus), ringed seals (Phoca hispida), and bearded seals (Eriginathus barbatus), inhabit a seasonably dynamic environment that has experienced climate-induced changes. During most seasons polar bears prefer mixed ice habitats near ice edges in shallow waters over the continental shelf. In past decades, polar bears could maintain this habitat preference for nearshore ice, but in recent years, extensive ice melt has forced most polar bears to summer in deepwater ice habitat more than 200 km from the mainland coast. A smaller segment of the population is forced to use shoreline habitat.

Other research suggests that prey resources may be diminished for polar bears force to occupy land and the deep water pack ice during summer. For example, the winter and spring distribution of ringed seals, the most important prey for polar bears, reflects the general distribution of polar bears. During summer, while some ringed seals may track the ice edge as it retreats north, others may have an open water life style and thus would be unavailable to polar bears. Bearded seals, due to their bottom-feeding habits, have not been available to polar bears summering over deep-water habitats during recent summers. In addition, a changing sea ice environment may affect reproduction of both predator and prey. A number of pregnant polar bears in Alaska den on the active sea ice, the thinning of which brings into question whether winter ice has the stability necessary for successful denning. Seals also depend on sea ice for birth and hence are also susceptible to changes in the composition of sea ice. George Durner and Steven Amstrup, Session 33, Tuesday, Sept. 26, 8:40-9:00 a.m.........

Posted by: Kelly      Permalink         Source

September 25, 2006, 9:16 PM CT

Groundbreaking Study By On Lions

In a groundbreaking study reported in the latest issue of the Journal of Zoology sheds light on several longstanding misconceptions regarding the controversial topic of mane variability among wild lions. This comprehensive scientific assessment of mane variation--including "manelessness"--is a first and took nearly seven years to complete.

As per the overall findings of the study, wild lions generally develop manes in accordance with local climate regimes. In Equatorial east Africa, climate is determined by elevation. Thus lions with the most profuse manes occur at the upper limit of their altitudinal range, while similar aged males in the lowest and warmest environments like Tsavo typically carry only modest or scanty manes.

However, the authors also found, paradoxically, that the majority of lions in regions like the greater Tsavo ecosystem (which is famed for its "maneless" lions), did appear to acquire respectable manes, eventually, contrary to most recent popular and scientific accounts of the lions from that region.

"We knew about the climate/elevation correlation since we were the first to publish those preliminary results in GEO 2001, but this new development really threw us for a loop," says Tom Gnoske, of the Field Museum's Zoology Department and senior author of the paper. "However once we analyzed all of the statistical data we found a very strong correlation linking increased age and continued mane development, a significant variable ignored by all prior authors." .........

Posted by: Kelly      Permalink         Source

September 25, 2006, 7:09 PM CT

Birds of Prince Edward Island

AND SO BEGINS Your Guide to Familiar Birds of Prince Edward Island, a pocket-sized, colour guide to some of the most sought out birds in the province. The book was compiled and written by legendary Island naturalist, the late Geoff Hogan, and published in 1991 by Ragweed Press, 222 Grafton St., Charlottetown.

In this handy, take-along paperback, Mr. Hogan has included 90 colour photos of everything from Eastern Kingbirds to Greater Yellowlegs. Accompanying text for each of these species and about 100 others outlines such details as habitat, when to find them and unique characteristics that will aid in identification.

Prince Edward Islanders have always enjoyed a unique relationship with nature. In a province where agriculture, fishing and tourism are the driving forces behind the economy, Islanders take very seriously the responsibility of being the guardians of one of Mother Nature's most glorious works of art.

In all, there are about 333 species of birds found in this rolling tapestry we here are so proud to call home. Therefore, from birders who have just bought their first set of binoculars to those who have travelled the world in order to add to their lists of lifetime sightings, there is something on PEI for everyone.

Considering the abundance of bird life in the province, it is not surprising that Prince Edward Island has become a bird-watching hot spot over the last several years, says Kate MacQuarrie, Executive Director of Island Nature Trust, a non-profit organization devoted to the protection and management of natural areas.........

Posted by: Kelly      Permalink         Source

September 25, 2006, 7:01 PM CT

The Spider Life Cycle

The spider life cycle progresses through three stages: the embryonic, the larval, and the nympho-imaginal.

The time between when an egg is fertilized and when the spider begins to take the shape of an adult spider is referred to as the embryonic stage. As the spider enters the larval stage, it begins to look more and more like an adult spider. It enters the larval stage as a prelarva and, through subsequent moults, reaches its larval form, a spider-shaped animal feeding off its yolk supply. After a few more moults (also called instars) body structures become differentiated. Soon, all organ systems are complete and the animal begins to hunt on its own; it has reached the nympho-imaginal stage.[2].

This stage is differentiated into two sub-stages: the nymph, or juvenile stage and the imago, or adult stage. A spider does not become sexually mature until it makes the transition from nymph to imago.[2] Once a spider has reached the imago stage, it will remain there until its death. After sexual maturity is reached, the general rule is that they stop moulting, but the females of some non-araneomorph species will continue to moult the rest of their lives.

A number of spiders may only live for about a year, but a number will live two years or more, overwintering in sheltered areas. The annual influx of 'outdoor' spiders into houses in the fall is due to this search for a warm place to spend the winter. It is common for tarantulas to live around twenty years.........

Posted by: Kelly      Permalink         Source

September 25, 2006, 6:47 PM CT

Galapagos Wildlife

Galapagos Wildlife

Reptiles.

There are 27 species of reptiles found on the Galapagos divided in five families as follows: snakes, geckos, Iguanas, lava lizards and, the giant tortoises.

Giant Tortoises (Geochelone elephantopus).

The Galapagos and the Seychelles are the sole islands housing giant tortoises while the Galapagos name originates from the Saddleback tortoise meaning galápago or saddle.

14 subspecies of this wonderful ancient has been located on the islands and 11 survive to this day. The most senior tortoise lives in the Darwin Research Station and is purported to be a grand 170. Longevity results through perhaps a stress free lifestyle as all their life consists of is eating, mating and sleeping with no predators at large in addition to nesting during February to May when the females prepare to lay their eggs which take between 3 to 8 months to hatch.

Today the Darwin Research station is helping to increase the current 15,000 population of giant turtles and along with the Santa Cruz tortoise reserve on San Cristobal housing the highest population of all islands the captivity approach is working effectively.

Marine Turtles (Chelonia mydas).

The pacific green turtle mates around December-January and lays its eggs from 80 up to over 100 in a hole in the darkness of night with Floreana beach being a popular area for the laying of their eggs.........

Posted by: Kelly      Permalink         Source

September 25, 2006, 6:30 PM CT

Nestled, Sharply

This bud or arm is growing about 16' above where the three previous plant structures (in the other photos) are growing.

I wonder if this is how a cactus "arm" grows. No doubt about it, the saguaro cactus is one amazing plant.........

Posted by: Erica      Permalink         Source

September 25, 2006, 6:19 PM CT

Wild Bees Better Pollinators

Up to a third of our food supply depends on pollination by domesticated honeybees, but the insects are up to five times more efficient when wild bees buzz the same fields, as per a research studypublished Aug. 28 in the journal Proceedings of the National Academy of Sciences of the USA.

"As honeybees become more scarce, it becomes more important to have better pollinators," said Sarah Greenleaf, a postdoctoral researcher at UC Davis and first author on the study.

As a graduate student at Princeton University, Greenleaf carried out a two-year study of honeybees used to pollinate sunflower crops on farms in Yolo County, Calif., near UC Davis.

In comparison to honeybees, wild bees did not contribute much directly to crop pollination. But on farms where wild bees were abundant, honeybees were much more effective in pollinating flowers and generating seeds, Greenleaf found.

There appear to be two reasons for that. Male wild bees, probably looking for mates, will latch onto worker honeybees, which are sterile females, causing them to move from one flower to another. Secondly, female wild bees appear to "dive bomb" honeybees, forcing them to move. Frequent movement between flowers spreads pollen around more effectively.

Greenleaf and her co-author Claire Kremen, now a professor at UC Berkeley, calculated that wild bees contributed about $10 million of value to the $26-million sunflower industry alone.........

Posted by: Kelly      Permalink         Source

September 25, 2006, 6:07 PM CT

Bugs In Fruits And Vegetables

A new method for ridding harvested fruits and vegetables of insect pests and microorganisms, without the use of ozone-depleting chemicals such as methyl bromide, has been developed by scientists at UC Davis.

The technique, called metabolic stress disinfection and disinfestation, effectively suffocates insects found in harvested produce. Inside sealed chambers, alternating vacuum forces and pressurized carbon dioxide applications cause irreversible changes in the animals' cell chemistry and respiratory structures. Ethanol gas also is applied briefly to accelerate killing of fungi and bacteria and to damage insect eggs.

In practice, the process would be applied to pallets of fruits and vegetables to prevent insect damage during storage and shipping, and to avoid transporting potentially invasive insects from one country to another. A patent is pending on the technology, which was published in the recent issue of the Journal of the Science of Food and Agriculture.

"All major fruits, including table grapes, citrus, apples, pears, bananas and kiwifruits, as well as vegetables and ornamental flowers, retain their quality when treated with this technology," said the developer, Manuel Lagunas-Solar, a research chemist at UC Davis' Crocker Nuclear Laboratory.........

Posted by: Kelly      Permalink         Source

September 24, 2006, 10:24 PM CT

Crickets on Hawaiian Island

In only a few generations, the male cricket on Kauai, one of the Hawaiian Islands, underwent a mutation a sudden heritable change in its genetic material that rendered it incapable of using song, its sexual signal, to attract female crickets, as per a new study by UC Riverside evolutionary biologists.

In addition, the scientists observed that eventhough the new male crickets' wings lack the file and scraper apparatus mandatory for producing sound, the males are able to mate successfully with females, thus ensuring evolutionary success. They accomplish this by simply altering their behavior in an ingenious manner, suggesting that behavior can help what may seem like a harmful mutation spread.

The research team, led by Marlene Zuk, a professor of biology, observed that greater than 90 percent of male field crickets (Teleogryllus oceanicus) on Kauai shifted in less than 20 generations from having normal wings to mutated "flat wings" that inhibit the crickets from calling. The mutation occurred, the scientists conclude, to protect male crickets from a deadly parasitic fly (Ormia ochracea) that uses the cricket song to locate crickets as hosts.

Upon finding a male cricket, the fly deposits larvae onto it; these then burrow into the cricket, develop inside, and subsequently kill the cricket when they emerge from its body. Of three Hawaiian Islands (Oahu, the Big Island of Hawaii, and Kauai) where the cricket and fly co-occur, Kauai, where the rapid spread of this wing mutation in male crickets was observed, has the highest prevalence of the parasitic fly.........

Posted by: Kelly      Permalink         Source

September 22, 2006, 4:51 PM CT

Watching The Fruit Fly Chromosomes In Action

Scientists are enthusiastically watching the chromosomes of the fruit fly in action over the specialized microscope. These fruit fly larvae, warmed in a toasty lab chamber, are giving clues to the gene expression and chromosome interactions. Researchers from Cornell researchers take these actions very seriously.

They are using multiphoton fluorescence microscopy, which is a technique pioneered at Cornell University by physicist Watt W. Webb. These researchers from Cornell have for the first time witnessed chromosomes change their form in order to activate their genes to synthesize key proteins in fruit fly cells. They say that this is a very important step toward understanding the basic processes that underlie gene expression.

The discovery was the result of cross-disciplinary collaboration between Webb and John Lis, Cornell's Barbara McClintock Professor of Molecular Biology and Genetics.

"This technology will revolutionize the way we see gene expression in organisms," said Lis. "We're watching transcription in real time in living cells."

These researchers have published their findings in the Aug. 31 issue of the journal Nature.

The research team focused their attention on gene regulatory mechanisms: specifically, what happens in a cell's nucleus when an external stimulus prompts specific genes to activate, and how those activated genes direct the production of proteins that protect the fly against the stress of heating.........

Posted by: Janet      Permalink         Source