Silk city

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A gigantic mass of spider webs spun in Lake Tawakoni State Park, about fifty miles east of Dallas, lent recent proof to the saying that "everything is bigger in Texas." Discovered early in August 2007, the webs stretched more than 250 feet long and 30 feet high, shrouding trees and bushes, making visitors think they were on the set of a Hollywood horror film. I got involved by answering park superintendent Donna Garde's plea for a spider expert to study the event in person.

Heading due south from Lawrence, Kansas, in nay old Chevy S-10 pickup truck, I mulled over the different theories set forth about the silken mass. Some scientists--speculating online, sight unseen--thought it was the result of a dispersal event. When weather conditions permit, large numbers of young spiders can fake to the air on silken parachutes. That so-called "ballooning" behavior enables them to travel quickly and colonize new locations, even islands. Perhaps a mass of ballooning spiders had landed and left behind a fine blanket of silk.

Others, including Mike Quinn, invertebrate biologist with the Texas Parks and Wildlife Department, believed a single species was largely responsible for building the impressive structure: a long-jawed spider named Tetragnatha guatemalenis. Since that species usually produces a relatively small spiral-shaped web, and the massive Tawakoni web appeared to be a jumble of silken strands, many of my colleagues and I were not convinced. I hoped to unravel the mystery for myself when, he day after Labor Day, I joined the approximately 4,000 people who had made the pilgrimage to north

The Tawakoni mass web surpassed any I had seen before: the spiders in it, of multiple species, numbered in the tens of thousands. I was immediately certain that this was woven--not a result of ballooning. As Quinn had predicted, long-jawed spiders were the primary architects, with some help from other orb weavers, cobweb spiders, and funnel web weavers. Together they had created an arachnid urban area--and we visitors were not unlike tourists tilting our heads back to gaze at New York City skyscrapers. The older webbing, in the center of the giant web, was a deteriorating downtown, chock-full of dead midges and mosquitoes--remnants of past meals.

There were pickpockets and murderers in abundance, too: black jumping spiders prowled the web in search of prey, and dewdrop spiders with shiny silver abdomens were stealing meals already secured by larger spiders. So why were all these spiders in one location? Were they cooperating to build a communal web? Or was this some paranormal phenomenon, as one individual in England proposed? Actually, the explanation was simple enough. Spiders, like most creatures, follow abundant sources of food. Heavy rains had pummeled the region during the summer months, creating the perfect breeding ground for mosquitoes and midges--the long-jawed spiders' favorite prey. Every day, just before dawn and just before dusk, I could hear a high-pitched whine as millions of them rose into the trees. With so much food flying around, the normally territorial spiders didn't mind crowding together.

When I returned three weeks later, however, the situation had changed dramatically. The food supply had tapered off, and it was every spider for itself. Cannibalism was rampant, as neighbors became potential prey. Portions of the giant web had been vacated. By the end of the year, rains had destroyed the remnants, and freezing temperatures killed any remaining spiders.

Yet thousands of egg sacs remain in the trees. Will the emerging spiderlings create another grand metropolis, or a famine-prone slum? Lake Tawakoni, which captured the interest of people around the globe, may warrant another visit very soon.

HANK GUARISCO is adjunct curator of arachnids at the Sternberg Museum of Natural History at Fort Hays State University in Hays, Kansas. He is currently writing a field guide to Kansas spiders.

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