November 22, 2006, 5:02 AM CT

How Many Cubs Does A Black Bear Have?

Litter size ranges from 1 to 4 young, averaging from 1.4 in Arkansas to 3.0 in Pennsylvania. First litters may be small, sometimes a single cub. Two or 3 cubs are typical thereafter. Five-cub litters are uncommon; extraordinary litters of 6 cubs have been reported in Manitoba and Pennsylvania. Average litter sizes in 2 Massachusetts study areas were 2.0 and 3.0. Two 5-cub litters have been reported in Massachusetts, once in the den and another in the field. Field observations are probably valid, as natural adoption of cubs is rare.

The sex ratio at birth is commonly 1:1. However, the sex of cubs is correlation to the mother's weight and to litter size. The number of males is commonly higher with heavier mothers, but lower as litter size increases. In one Minnesota study, 82% of single litters were male, while only 52% of 3-cub litters were males. One exceptional Massachusetts sow, 13 yrs old and 175 lbs., produced a litter of 5 male cubs.

During the denning period, sows may produce more than 50 lbs. of milk, metabolized from body fat. This milk is rich in fat and protein and nearly twice as high in kilocalories (per 100 ml) than either human or cow milk. Cubs may weigh up to 9 pounds by den emergence. Massachusetts cubs normally reach 13 to 20 lbs. by early July.........

Posted by: Kelly      Permalink

November 21, 2006, 5:13 AM CT

Clues From Dragonfly About Human Obesity

Parasite-infected dragonflies suffer the same metabolic disorders that have led to an epidemic of obesity and type-2 diabetes in humans, reveal the findings of research conducted at Penn State University that are due would be published in the 5 December 2006 issue of the Proceedings of the National Academy of Science and also in the PNAS early online edition at www.pnas.org on 21 November. The discovery expands the known taxonomic breadth of metabolic disease and suggests that the study of microbes found in human intestines may provide a greater understanding of the root causes of human metabolic dysfunction.

James Marden, professor of biology and an insect physiologist at Penn State, and Ruud Schilder, who in August 2006 earned his doctorate in biology at Penn State and is now a postdoctoral fellow at the University of Nebraska, are the first to show a non-mammalian species suffering from metabolic dysfunction in ways similar to humans. "Metabolic disease isn't some strange thing having just to do with humans," said Marden. "Animals in general suffer from these symptoms".

The work is also novel because it links metabolic disease to a supposedly harmless parasite living in the dragonfly's gut. The parasites, known as gregarines, belong to the Apicomplexa, a group of microorganisms that includes protozoa, which cause diseases like malaria and cryptosporidiosis. The dragonfly species that Marden and Schilder studied is Libellula pulchella. The microbes disrupting the dragonfly metabolism may hold clues for scientists looking for the root causes of metabolic diseases in humans, according to Marden and Schilder's paper.........

Posted by: Kelly      Permalink         Source

November 20, 2006, 5:12 AM CT

Monarch Butterfly Migration And Forest Restoration

USDA Forest Service (FS) research in the Ouachita Mountains of Arkansas suggests that decades of fire suppression have reduced the area's food supply for migrating monarch butterflies-and that restoration efforts that include prescribed burning can reverse this trend. Craig Rudolph and Ron Thill, research ecologists with the FS Southern Research Station (SRS), along with SRS ecologists Charles Ely, Richard Schaefer and J. Howard Williamson, report their findings in the latest issue of the Journal of the Lepidopterists' Society.

Every fall, masses of monarch butterflies migrate across eastern North America to remote sites in central Mexico-a long flight fuelled only by nectar from flowers still blooming on the way. In recent years, there have been concerns about the continued health of monarch populations, and of the migration itself, as land use change has altered both breeding habitat and migratory pathways.

Studies have focused on food availability for larvae, pesticides, and loss of overwintering sites in Mexico as possible threats. Less attention has been paid to how landscape-level changes affect the availability of the butterfly's preferred nectar sources along their migratory routes. In September and October, large numbers of monarchs pass through the Ouachita Mountains, a largely forested area in Arkansas and Oklahoma where fire suppression, logging, and pine production practices have altered forest structure, leading to a drastic reduction in the quality and abundance of the flowering plants the butterflies rely on for nectar.........

Posted by: Kelly      Permalink         Source

November 19, 2006, 9:01 PM CT

Which Wasps Are Bad Losers

Wasps have more than just a sting in their tail as per new research published this week in the Proceedings of the Royal Society B, they also carry the insect version of pepper spray in their heads, which they can release when fighting other wasps. The research not only gives us a fascinating insight into insect behaviour but could also help us to use wasps to kill crop destroying pests.

For the first time scientists, funded by the Biotechnology and Biological Sciences Research Council (BBSRC), have recorded 'chemical exchanges' undetectable by the human nose which take place between females of a species of bethylid wasp - Goniozus legneri, when they fight over larvae on which they lay their eggs. Not only have they discovered that chemical exchanges take place, but also that it is always the losing wasp that releases the potent gas.

While the research was primarily aimed at improving the understanding of animal behaviour, lead researcher Dr Ian Hardy, from the University of Nottingham, explains that there is great potential for applied spin-offs: "Bethylid wasps kill the larvae of a number of insects that are pests of crops, such as almonds, coffee and coconut, ruining harvests and costing industry thousands of pounds. These wasps could be used as a cheap and effective biological control to kill the larvae, avoiding the use of expensive and polluting pesticides. But for successful biological control, we need a good knowledge of wasp behaviour, including how wasps from the same and different species interact. Understanding these patterns can inform us of the best combinations of species to release against a given crop pest." .........

Posted by: Kelly      Permalink         Source

November 19, 2006, 8:57 PM CT

Fighting Like A Girl Or Boy

Fighting like a girl or fighting like a boy is hardwired into fruit fly neurons, as per a research studyin the Nov. 19 Nature Neuroscience advance online publication by a research team from Harvard Medical School and the Institute of Molecular Pathology in Vienna. The results confirm that a gene known as "fruitless" is a key factor underlying sexual differences in behavior. The findings mark a milestone in an unlikely new animal model for understanding the biology of aggression and how the nervous system gives rise to different behaviors.

"Aggression is a very serious problem in society, and it's a problem with a biological and genetic component," said co-author Edward Kravitz, the George Packer Berry professor of neurobiology at HMS, who developed the fruit fly fighting model used. "We want to understand that. I can't think of a better system to study than fruit flies. And no one gets hurt".

The fruitless gene is known for its role in male courtship. The large gene makes a set of male-specific proteins found exclusively in the nervous system of fruit flies, in about 2 percent of neurons. The proteins are necessary for normal courting. Males missing the proteins do not court females, and they sometimes court males, other research groups have shown. Females with a male version of the gene perform the male courting ritual with other females.........

Posted by: Kelly      Permalink         Source

November 16, 2006, 9:53 PM CT

Emperor Penguin Physiology

Long before they lit up movie screens in animated feature films or enthralled documentary film audiences worldwide with the story of their endless struggle to survive and reproduce, Emperor penguins intrigued early Antarctic explorers.

As movie makers prepare this weekend to release "Happy Feet," about an animated Emperor who loves to dance, and the Hallmark Channel readies the cable-television premier of the documentary "March of the Penguins" on Sat., Nov. 25, 2006, the National Science Foundation (NSF) is making available B-roll of the penguins in Antarctica. The agency is also offering journalists the opportunity to ask Antarctic scientists questions about why the birds still challenge the scientific mind.

On the eve of International Polar Year (IPY), Emperor penguins, which can dive unharmed to depths that no human could survive unaided, still fascinate researchers.

By studying the animals' physiology and the way their bodies respond to the crushing pressure of deep dives, these NSF-funded scientists, who also are medical doctors, may one day provide clues to help improve surgical procedures and anesthesia. The study of Emperors also is very much in the spirit of NSF's IPY theme of attempting to understand what makes the processes of life in the cold and dark unique.........

Posted by: Kelly      Permalink         Source

November 16, 2006, 9:45 PM CT

Different Coat Color doesn't Mean Different Species

Scientists have observed that lemurs suspected to belong to different species because of their strikingly different coat colors, are not only genetically alike, but belong to the same species.

Historically, species classification has been based on comparison of visible physical characteristics of plants or animals. Kellie Heckman, a post-doctoral fellow in ecology and evolutionary biology at Yale, and her colleagues at other universities, used analysis of a mitochondrial gene, cytochrome b, to test the genetic relationship of 70 lemurs that were believed to be long to up to three different species. Their report was reported in the open access journal BMC Evolutionary Biology.

"Our study combined morphological, genetic, geographic, and ecological data giving a multidimensional, and hopefully more accurate picture of species diversity," said Heckman. "Over the past decade, the number of proposed species of these lemurs has jumped from two to fifteen, based on physical differences. It pointed to the need for caution when identifying new species solely on the basis of visual or genetic characteristics."

The lemurs they tested had three extremely different coat colors and lived in different types of forest locations in southern Madagascar - classic characteristics of separate species. These scientists chose to compare mitochondrial cytochrome b as a gene marker that is known to change at a rate similar to that of speciation. Other common nuclear genes may evolve more slowly or more rapidly with population drift.........

Posted by: Kelly      Permalink         Source

November 16, 2006, 4:58 AM CT

Key To Controlling Gypsy Moth Spread

Controlling population peaks on the edges of the gypsy moth range may help to slow their invasion into virgin territory, as per a team of researchers.

"Slowing the spread of the gypsy moth is a priority in forest management in the U.S.," says Ottar Bjornstad, associate professor of entomology and biology, Penn State. "Understanding the underlying patterns in the spread of invasive species is important for successful management".

The accidental release of the gypsy moth in 1869 in Massachusetts has led to an infestation covering more than 386,000 square miles of the U.S. Northeast. Native to Europe and Asia, gypsy moths are currently found from Maine to North Carolina and west into Wisconsin where they defoliate trees and occasionally, cause extensive damage to northern deciduous forests.

"We analyzed historical data on the spread of the gypsy moth in the U.S. and observed that its invasion has been characterized by regular periods of rapid spread interspersed between periods of little expansion," says Bjornstad. "This is the first identification of pulsed invasions for an invading species".

Bjornstad; Derek M. Johnson, Department of Biology, University of Louisiana, and Andrew M. Liebhold and Patrick C. Tobin, U.S. Forest Service, used historical, county-level quarantine records as well as forest service data from more than 100,000 pheromone traps set along the expanding gypsy moth population front for their theoretical model. The pheromone trap data were collected from 1988 to 2004.........

Posted by: Kelly      Permalink         Source

November 13, 2006, 9:08 PM CT

Where Chimp And Human Brains Diverge

Six million years ago, chimpanzees and humans diverged from a common ancestor and evolved into unique species. Now UCLA scientists have identified a new way to pinpoint the genes that separate us from our closest living relative and make us uniquely human. The Proceedings of the National Academy of Sciences reports the study in its Nov. 13 online edition.

"We share more than 95 percent of our genetic blueprint with chimps," explained Dr. Daniel Geschwind, principal investigator and Gordon and Virginia MacDonald Distinguished Professor of Human Genetics at the David Geffen School of Medicine. "What sets us apart from chimps are our brains: homo sapiens means 'the knowing man.'.

"During evolution, changes in some genes altered how the human brain functions," he added. "Our research has identified an entirely new way to identify those genes in the small portion of our DNA that differs from the chimpanzee's."

By evaluating the correlated activity of thousands of genes, the UCLA team identified not just individual genes, but entire networks of interconnected genes whose expression patterns within the brains of humans varied from those in the chimpanzee.

"Genes don't operate in isolation each functions within a system of related genes," said first author Michael Oldham, UCLA genetics researcher. "If we examined each gene individually, it would be similar to reading every fifth word in a paragraph you don't get to see how each word relates to the other. So instead we used a systems biology approach to study each gene within its context."........

Posted by: Kelly      Permalink         Source

November 10, 2006, 4:08 AM CT

Sea Urchin Genome And Human

The Sea Urchin Genome Sequencing Project (SUGSP) Consortium, led by the Human Genome Sequencing Center at Baylor College of Medicine (BCM-HGSC) in Houston, announced recently the decoding and analysis of the genome sequence of the sea urchin, Strongylocentrotus purpuratus.

The genome of a male California purple sea urchin was sequenced, and it contained over 814 million letters, spelling out 23,300 genes. Nearly 10,000 of the genes were scrutinized by an international consortium of 240 researchers from over 70 institutions in 11 countries. The high quality "draft" sequence covers over 90 percent of the genome. The primary results are presented in the Nov. 10 issue of Science, and 41 companion manuscripts describing further detailed analyses are contained in Science and a special issue of Developmental Biology appearing on Dec. 1.

The BCM-HGSC generated the sequence data for the SUGSP, then assembled the genome and led the analysis consortium. Additional resources for the project included a BAC library (clones with very large pieces of DNA) prepared at the California Institute of Technology and a physical map prepared at the Michael Smith Genome Sciences Centre at the British Columbia Cancer Agency in Vancouver.

The project was led by Drs. Erica Sodergren and George Weinstock, a husband and wife team at the BCM-HGSC, along with Dr. Richard Gibbs, director of the BCM-HGSC, and Drs. Eric Davidson and Andrew Cameron of the California Institute of Technology. The National Human Genome Research Institute of the National Institutes of Health provided most of the funding for the SUGSP.........

Posted by: Kelly      Permalink         Source