Joro Spiders Making Their Mark Across the U.S.

There’s a new player in the spider world: the Joro spider. These palm-sized arachnids are crafting massive, shimmering webs on porches and power lines everywhere. And it looks like they’re here to stay.

First spotted in Georgia back in 2013, Joro spiders can stretch their legspan to about four inches, sporting vibrant neon yellow, blue-black, and even red markings. Experts believe they’ve been making their way north, possibly hitching rides on shipping containers or planes.

These spiders have already made appearances in several states, including Georgia, North Carolina, South Carolina, and Tennessee. It’s anticipated that their territory will extend throughout eastern North America, reaching as far as Pennsylvania and potentially warmer coastal regions.

One interesting ability these spiders possess is called ballooning. This technique allows their hatchlings to release fine silk threads that the wind carries over long distances.

Ian Williams, an entomologist from Orkin, noted that he found around 200 adult Joros on a single acre in Atlanta last September. “They certainly look intimidating, and their webs are quite large,” he mentioned, pointing out how the sunlight gives the webbing a golden hue.

But before anyone panics, experts reassure that these spiders are relatively shy. Joros tend to remain motionless for extended periods when disturbed, which is interesting considering their formidable appearance.

Interestingly, even though they boast large bodies, their fangs aren’t particularly big, making it hard for them to bite humans. If a sting happens, the venom is relatively weak—comparable, really, to a common bee sting, and it’s not considered a medical concern.

Still, scientists are pondering the implications of Joros as an invasive species. There’s concern that they might compete with local spider populations for resources.

Joros are effective predators, often hunting a range of insects from mosquitoes to larger prey like cicadas. Yet, it’s unclear if they interfere with garden spiders’ hunting efforts.

For those wanting to deter these spiders from making a home on their property, experts recommend physically removing nests using a broom or a long stick. Williams pointed out, “The spider might take the hint and decide not to rebuild in the same spot.”

Physical removal is generally seen as more effective than pesticides, which often fail to reach spiders in their elevated nests. For anyone who happens to spot a black widow spider in new areas, jotting down those sightings on an app like iNaturalist can help researchers track their movements.