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Thousands Of Spiders In Dallas Suburb Build Incredibly Rare Mega-Web

Mike Merchant
Texas A&M Agrilife Dallas
Long-jawed spiders hunting from a communally built mega-web near Lake Ray Hubbard in Rowlett.

Some people are afraid of spiders. And most spiders don’t like other spiders, either -- they often eat each other. In North Texas, a strange thing has happened. Thousands of spiders worked together to build a communal mega-web -- it's about 40 feet high and as long as a football field. 

Here's what you need to know about this unusual spider web.

How was the web discovered? 

"So this web was discovered in late July by just somebody driving down the street and it's over close to [Lake Ray Hubbard] in Rowlett," said Mike Merchant, an entomologist with the Texas A&M Agrilife Extension Service in Dallas. "It's just kind of an unusual phenomena. We don't normally see spiders working together to make a web. In this case, somebody just noticed. 'Hey there's a lot of white stuff all over those trees. What is it?'"

How do spiders normally treat each other?

"Usually, spiders don't like hanging out around other spiders," Merchant said. "Another spider is going to be competition for food and for web space. So normally they keep their distance from one another."

Credit Mike Merchant / Texas A&M Agrilife Dallas
Texas A&M Agrilife Dallas
A vial of 'Tetragnatha guatemalensis' or long-jawed spiders collected from the Rowlett mega-web.

A changing web

At first, when Merchant visited the web, he said it was beautiful, "pristine and gossamer and shining and covered all the tips of the branches."

"Kind of spooky-looking, but still kind of pretty."

But the next day, he went out with a colleague and the web looked different. "The character and quality of the web was much diminished from the first day," he said.

What happened?

Merchant discovered Dallas County had sprayed the area the night before -- the area had tested positive for West Nile virus. Merchant called a friend in the county health department.

"He said: 'Oh, we just won't spray that street anymore; thanks for letting us know.' They were very happy to accommodate the spiders. As far as they're concerned they don't want to hurt spiders either because they eat mosquitos."

But the damage had apparently been done. The web is on the decline, Merchant said. 

What spiders would work together to build a web?

"The name of the species is 'Tetragnatha guatemalensis.' The simple English name is long-jawed spider," Merchant said. "The male uses these jaws to grasp the female's jaws so she doesn't eat them while they're mating. And it's a very interesting spider when you see it up close."

How often are these webs built?

"There are spiders known to be social, but typically the social webs might be two or three females in a single web helping raise young -- but nothing on the scale like these long-jawed spiders. We knew that other spiders would build webs together. We just didn't ever see it on the scale or with this particular species or family before."

In 2007, a huge spider web was spotted at Lake Tawakoni State Park.

Mike Merchant is an entomologist with the Texas A&M Agrilife Extension Service in Dallas.
