Joro spiders multiply across Georgia, spinning their pesky webs

Have you walked face-first into a large spider web on your porch this summer? Of course you have.

It could belong to a Joro spider, the large, yellow-and-black orb weavers.

Atlantans are becoming well acquainted with the invasive species that, to some, seems to be taking over the city. But how prevalent are these East Asian spiders, and are they multiplying as rapidly as it appears?

Perhaps most importantly, how can anyone escape from their tangled webs?

“They’re everywhere,” said Andy Davis, a University of Georgia research scientist who began studying Joro spiders after they invaded his Athens backyard. “They’re pretty much on every building, every outbuilding, my garage, over the trees in my yard.”

The large, invasive Joro spider is distinctive with black-and-yellow legs and other markings. (Charles Seabrook for The Atlanta Journal-Constitution)

Research shows they have multiplied rapidly throughout North Georgia. Robert Pemberton, an independent researcher and retired entomologist with the USDA Agricultural Research Service, called their growth “dramatic” and “quite impressive.”

“There’s no reason to be afraid of them, although the webs are certainly a nuisance when they become really abundant, like in my own yard,” Pemberton said in an interview with The Atlanta Journal-Constitution.

Joro spiders are believed to have come to North America in 2014, likely stowed away in shipping containers, from their homes in Japan and East Asia. They pose no threat to humans — beyond their strong webs blocking doors and paths around homes and in parks during their peak season, from August to mid-fall.

And they multiply incredibly quickly.

They have also spread beyond Georgia, in part by hitchhiking on vehicles. Scientists predict they will eventually be found all along the East coast. Last fall, one was spotted as far north as Boston, researchers say.

Part of what makes them unique is their ability to live in urban and rural environments, undeterred by the noise and bustle surrounding the architectures to which they cling.

Despite their bold appearance, these spiders appear to be more afraid of us than we are of them. Davis has studied the Joros in his lab and said he found them to be “one of the shyest spiders of all time.”

“They’re not going to jump out of their web and attack you like some people think,” Davis said.

In fact, the Joros aren’t harmful to people or animals. Their bites are very rare and cause only mild swelling, he said.

“They’re a nuisance to people. Nobody likes them,” Davis said. “And it’s especially not good when you walk into a web, because they’re big webs, and you get a face full of spider web, and it’s not pleasant.”

But killing them or spraying your yard with pesticides is not the solution, he added. The chemicals would also kill all other insects, which negatively impacts the ecosystem.

Some birds are already beginning to prey on the Joros. Pemberton said he observed red cardinals going after the spiders in his garden, which could eventually level off their large population numbers.

A male cardinal stares at a Joro spider in a yard in Decatur. The bird was observed stealing small insects and other morsels trapped in the spider's web. (Courtesy of Charles Seabrook)

“Some invasive species, when they first come into an area, they can have very high populations,” Pemberton said. “As local predators and parasites learn to use them, then they can be knocked back. But we don’t really know what will happen here.”