Ecologist finds spider webs strong enough to hold birds

Joro spider (Photo by Dorothy Kozlowski)

Andy Davis, assistant research scientist in the Odum School of Ecology, spoke with National Geographic about Joro spider webs, seemingly strong enough to hold a bird.

“This is incredibly unusual,” said Davis. “To the best of our knowledge, this is a scientific first.”

When helping his son with his science project, Davis attempted to measure the strength of Joro spider webs, a species on which Davis is an expert. He measured that the webs could hold up to 69 grams, easily strong enough to support a common bird like the cardinal.

“Four or five months later, this guy calls me and says he’s found a bird sitting on a web,” said Davis. “And then I kind of put two and two together and realized that I had data that basically showed the same thing.”

Joro spiders have made a major impact along the east coast after hitching a ride from Asia. While not harmful, their population has exploded in a new habitat. Their webs now offer a valuable food source to birds, and even other spiders.

“These little spiders, [dewdrop spiders], kind of make their living hanging out on other spider’s webs and stealing their food,” said Davis. “In all the Joro webs I’ve seen this fall, I’ve probably seen these dewdrop spiders on at least 30 percent of them. So, the dewdrops are benefitting big time from the Joros.”