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.........
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September 25, 2006, 6:47 PM CT
Galapagos Wildlife
Galapagos WildlifeReptiles.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.........
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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.........
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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
Parasitized male cricket
Credit: J. Rotenberry, UCR
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 21, 2006, 4:58 AM CT
Hidden Messages From Squid Skin
In the animal world, squid are masters of disguise. Pigmented skin cells enable them to camouflage themselves-almost instantaneously-from predators. Squid also produce polarized skin patterns by regulating the iridescence of their skin, possibly creating a "hidden communication channel" visible only to animals that are sensitive to polarized light.
In research published recently in the journal Biology Letters, MBL (Marine Biological Laboratory) scientists Lydia Mäthger and Roger Hanlon present evidence that the polarized aspect of the skin of the longfin inshore squid, Loligo pealeii, is maintained after passing through the pigment cells responsible for camouflage.
While the notion that a few animals produce polarization signals and use them in communication is not new, Mäthger and Hanlon's findings present the first anatomical evidence for a "hidden communication channel" that can remain masked by typical camouflage patterns. Their results suggest that it might be possible for squid to send concealed polarized signals to one other while staying camouflaged to fish or mammalian predators, most of which do not have polarization vision.
Mäthger notes that these messages could contain information regarding the whereabouts of other squid, for example. "Whether signals could also contain information regarding the presence of predators (i.e., a warning signal) is speculation, but it may be possible," she adds.........
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September 21, 2006, 4:52 AM CT
New Link In The Evolution Of Immunity
Gray whale
Scientists from the University of Pennsylvania School of Veterinary Medicine have discovered a unique evolutionary link between the immune systems of fish and mammals in the form of a primitive version of B cells, white blood cells of the immune system. Their studies link the evolution of the adaptive immune system in mammals, where B cells produce antibodies to fight infection, to the more primitive innate immunity in fish, where they observed that B cells take part in phagocytosis (literally: cell eating), the process by which cells of the immune system ingest foreign particles and microbes.
The finding, which appears in the online version of Nature Immunology and will be featured on the cover of the October issue, represents a sizeable evolutionary step for the mammalian immune system and offers a potential new strategy for developing much-needed fish vaccines.
"When examining fish B cells we see them actively attacking and eating foreign bodies, which is a behavior that, as per the current dogma, just shouldn't happen in B cells," said J. Oriol Sunyer, a professor in Penn Vet's Department of Pathobiology. "I believe it is evidence for a very real correlation between the most primitive forms of immunological defense, which has survived in fish, and the more advanced, adaptive immune response seen in humans and other mammals".........
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September 20, 2006, 10:07 PM CT
Obesity Crisis in Insects?
The response of caterpillars to extreme nutritional environments was studied in a joint research project by a Texas Agricultural Experiment Station researcher and others.
Ever seen a fat insect? Probably not. Dr. Spencer Behmer may have the answer why, and that could have implications for what is billed as the current human obesity epidemic.
Behmer, an entomologist with the Texas Agricultural Experiment Station, and several other scientists conducted a series of experiments to find out whether caterpillars could adapt to extreme changes in their nutritional environment.
By manipulating the nutritional environment of the diamondback moth caterpillars, the scientists observed that the insects evolved different physiological mechanisms correlation to fat metabolism. Which mechanism was used depended on whether the caterpillars were given carbohydrate-rich or carbohydrate-poor food.
The team's work was published recently in the Proceedings of the National Academy of Science.
The scientists theorized caterpillars - and animals in general - can evolve metabolically to adjust to extreme nutritional environments.
All animals need carbohydrates for energy and protein to build muscle and tissue, Behmer said. Different animals, however, need different amounts of these two macronutrients and sometimes it can be literally feast or famine for one or both of them.
"It's difficult to find in any environment a nutritionally perfect food," he said.........
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September 20, 2006, 10:03 PM CT
Corn And Soy Plastics To Be Made Into Hog Feeders
Richard Larock displays some of the plastics he has made from corn, soybean and other bio-based oils.
Richard Larock sorted through a pile of neatly labeled baggies filled with the plastics he makes from corn, soybean and other bio-based oils.
Larock, a University Professor of chemistry at Iowa State University, found the thin, square piece he was looking for and smacked it against his hand. This one is made from soybean oil reinforced with glass fibers, he said. And it's the kind of tough bioplastic he and his industrial collaborators will use to develop, test and manufacture new hog feeders.
Larock said his research project is about as Iowa as you can get. The state, after all, is the country's leading producer of corn, soybeans and pork.
The project is partially supported by a grant of $96,000 from the Grow Iowa Values Fund, a state economic development program. Larock is working with AgVantage Inc., a Rockford, Ill., company with manufacturing facilities in Iowa, and R3 Composites, a Muscatine manufacturer.
Larock has invented and patented a process for producing various bioplastics from inexpensive natural oils, which make up 40 percent to 80 percent of the plastics. Larock said the plastics have excellent thermal and mechanical properties and are very good at dampening noises and vibrations. They're also very good at returning to their original shapes when they're heated.........
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September 20, 2006, 8:55 PM CT
Champion Lost in the Fog Euthanized
Lost in the Fog, last year's Eclipse Award-winning sprinter, was euthanized Sept. 17, three weeks after doctors found three malignant tumors in his spleen and along his back.
The charismatic champion with the crooked blaze began his career with 10 consecutive victories, a streak that was broken when he finished unplaced in the 2005 TVG Breeders' Cup Sprint (gr. I) at Belmont Park.
"We accomplished what we wanted to do," said trainer Greg Gilchrist Sept. 18. "It was all about giving him quality (time). We did everything we could for him. He was happy and content right up to the end. He went quietly and easily".
Gilchrist had just finished grazing Lost in the Fog outside his barn at Golden Gate Fields on the San Francisco Bay Sept. 17, which he did twice daily, and was heading to the paddock to saddle a horse when Lost in the Fog went into distress.
During a teleconference held later in he day, Gilchrist said it was tough to say goodbye to Lost in the Fog.........
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