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The Giant Spider Web at Lake Tawakoni

There is a giant spider web at Lake Tawakoni State Park in Texas. The web was found in August by Texas Parks & Wildlife employee Freddie Gowin while mowing the trails at Lake Tawakoni State Park. The web sparked interest from experts and bloggers when Donna Garde, Lake Tawakoni State Park Superintendent, posted her photo of the web -- click here to see a larger version of the web photo. Wired says that thousands of spiders from 12 different species have built the web that reaches 200 yards. Normally, the spiders are competitors and enemies, and work individually on their own orb-shaped webs. But entomologists say that bountiful insect hatches caused by heavy rainfall have provided so much food that the spiders instinctively repressed their traditional enmities in favor of cooperation. It's a population-level evolutionary behavior that's never before been witnessed (and thank goodness for that; spiders are scary enough on their own!) The web, first reported earlier in the summer, took more than a month to build; it's been blown down three times by wind and rain, and re-spun each time. Visitors describe the web as something out of science fiction. Said a park volunteer, "Hollywood couldn't have done as good a job in their best day as nature has done with this." In the movie Arachnophobia a new species of spiders was discovered in South America that operates more like organized army ants and killer bees than solitary spiders. Fortunately, these Lake Tawakoni spiders are neither poisonous or very scary. This website provides a great timeline of the social spider web. This webpage contains a list of the spiders collected from the Lake Tawakoni web. And some more informaton about social spiders and links to more webs can be found here. More coverage of the spider web in articles and blog posts can be found here, here, here, here, here, here, here, here, here, here, here, here, here, here, here, here, here, here, here, here, here and here. Here's a video clip of the web. Direct video link Permalink | Recent Headlines | News Feeds Read more…

Dawn Of Animal Vision Discovered

18.10.2007 13:44 Science - Source: ScienceDaily Headlines

Science Daily — By peering deep into evolutionary history, scientists at the University of California, Santa Barbara have discovered the origins of photosensitivity in animals.

Opsin genes (blue) are present and expressed in the cnidarian Hydra. (Credit: David Plachetzki/UCSB)

The scientists studied the aquatic animal Hydra, a member of Cnidaria, which are animals that have existed for hundreds of millions of years. The authors are the first scientists to look at light-receptive genes in cnidarians, an ancient class of animals that includes corals, jellyfish, and sea anemones.

"Not only are we the first to analyze these vision genes (opsins) in these early animals, but because we don't find them in earlier evolving animals like sponges, we can put a date on the evolution of light sensitivity in animals," said David C. Plachetzki, first author and a graduate student at UC Santa Barbara. The research was conducted with a National Science Foundation dissertation improvement grant.

"We now have a time frame for the evolution of animal light sensitivity. We know its precursors existed roughly 600 million years ago," said Plachetzki.

Senior author Todd H. Oakley, assistant professor of biology at UCSB, explained that there are only a handful of cases where scientists have documented the very specific mutational events that have given rise to new features during evolution.

Oakley said that anti-evolutionists often argue that mutations, which are essential for evolution, can only eliminate traits and cannot produce new features. He goes on to say, "Our paper shows that such claims are simply wrong. We show very clearly that specific mutational changes in a particular duplicated gene (opsin) allowed the new genes to interact with different proteins in new ways. Today, these different interactions underlie the genetic machinery of vision, which is different in various animal groups."

Hydras are predators, and the authors speculate that they use light sensitivity in order to find prey. Hydra use opsin proteins all over their bodies, but they are concentrated in the mouth area, near the tip of the animal. Hydras have no eyes or light-receptive organs, but they have the genetic pathways to be able to sense light.

The findings are published in PLoS One. Co-author Bernie M. Degnan, of the University of Queensland in Brisbane, Australia, provided bioinformatics tools to complete the study.

Note: This story has been adapted from material provided by University of California - Santa Barbara.