While traveling down CA Roan Drive in Rowlett recently, people have been exposed to an eerie sight on a number of trees lining that route, said Mike Merchant, Texas A&M AgriLife Extension Service urban entomologist in Dallas.

Glistening webs are draping the trees like shrouds at Lakeside Park, near Lake Ray Hubbard.

Someone stepping off the road for a closer look will see thousands of lanky spiders darting among the webs that extend up to 40 feet into the trees, Merchant said. There is a surreal quality to the extensive webbing covering these trees.

Merchant said while rare, it is not unheard of that such massive web-works may appear once in a while. For example, he said, in 2007 the media reported about a giant spider web found at Lake Tawakoni State Park, about 35 miles from Rowlett. The spiders responsible for the nest construction were ultimately identified as Tetragnatha guatemalensis.

Arachnologists had previously noted that this species is known to build communal nests when conditions are right, he said. But it is rare to see them building such large nests in the U.S. Spider experts have indicated that those ‘right conditions’ appear to include a glut of small insects like midges that emerge at night from lakes. Without lots of food, these communal webs just don’t seem to form.

The spiders are not aggressive to other spiders of the same species in the web and are not known to bite humans. Because of their lack of aggression, Merchant said there is really no need to treat for them.