For residents of the southeastern United States, fall signals the return of Joro spiders—huge, bright yellow arachnids from Asia—haunting porches, gardens, and just about anywhere big enough for casting enormous webs.
Joros don’t typically pose serious threats to humans. But their autumnal abundance does appear to be the source of significant irritation for local residents—something that David Coyle, an entomologist at Clemson University, knows better than most, as South Carolina’s state advisor for invasive species.
After years of fielding Joro-related complaints, Coyle and his team decided to officially investigate these inquiries—a years-long effort resulting in two studies addressing the most common questions about Joro spiders, published Wednesday, October 22, in the Journal of Medical Entomology and the Journal of Economic Entomology.
Gizmodo spoke with Coyle about the spiders and shared tips for dealing with unwanted Joro encounters. The following conversation has been lightly edited for grammar and clarity.
Gayoung Lee, Gizmodo: What are Joro spiders, and why are they considered invasive?
David Coyle: Joro spiders are native to China and parts of Asia. They first got to the U.S. probably around 2010 but were first discovered in 2014 in northern Georgia. Since then, they’ve spread to multiple states, even all the way up into the Northeast. There are populations in and around Baltimore, Boston, and Pennsylvania. The hotspots are definitely northern Georgia, western South Carolina and North Carolina, and far eastern Tennessee.
They are an invasive species because… well, they’re not native to this continent, and they show pretty significant displacement of native species. This is the fifth year of our “spider surveys,” as we call them.
And, where you have high populations of Joro spiders, you have little to no native or weaving spiders of that type. It’s still too early to know what their true impact will be, but we’re trying to track that down.
Gizmodo: Why do people consider Joros pests?
Coyle: They’re incredibly pestiferous, in that they are very comfortable being in and around human structures and landscapes. They won’t go inside a house at all, but they’ll be on your bushes, on the carport, on the deck, and across doorways. They’re also very big and yellow, so people notice them, and we get lots of calls about these things every fall.
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