ARI SHAPIRO, HOST:
Summertime in the southeastern U.S. brings long, hot days, sometimes oppressive humidity and in many areas, yards full of Japanese Joro spiders. From member station WUGA in Athens, Ga., Martin Matheny reports that in many ways, this prolific, harmless creature is still a mystery to researchers.
MARTIN MATHENY, BYLINE: Two years ago, ecologist Andy Davis found himself compelled to become a Joro spider expert.
ANDY DAVIS: So I'm not a spider biologist by trade, but because they're in my backyard by the thousands, I simply had to become one.
MATHENY: Last month, Davis took me on a walk in the woods near the University of Georgia looking for the spiders. They're small in early summer, about the size of a pea or a grain of rice. That makes them hard to see, but Davis says they're out here. And after some walking, we spot one.
DAVIS: That's it right there. That little guy.
MATHENY: Wow, it's tiny.
DAVIS: And there's another one right there.
MATHENY: In a few months, these tiny grains will be huge, over an inch or more. And they'll be everywhere just in time for Halloween.
LAURA NEY: They have a yellow coloring with these sort of greenish-blue bands across their back.
MATHENY: Laura Ney is an extension agent in Athens. She works with farmers and gardeners on all things outdoors, including Joro spiders.
NEY: And they have large legs with banding, so they're pretty striking. They're actually, you know, an attractive spider (laughter) to view.
MATHENY: Joro spiders first appeared in Georgia nearly 10 years ago, likely by hitching a ride on a shipping container from Southeast Asia. In 2019, when Joros started to pop up in large numbers in north Georgia, Ney got a lot of questions about them.
NEY: What is this? We've never seen it before. This is a different looking spider. And of course, one of the first concerns is, is this dangerous?
MATHENY: Joro spiders are completely harmless to humans. But as to their effect as an invasive species, the Joro jury is still out.
NEY: There's no evidence that's been recorded so far that they're having a detrimental effect. But of course, I mean, in the grand ecological scheme of things, they've only been here for a really short period of time.
MATHENY: But in that time, ecologist Andy Davis has already discovered a few things. For example, they're more comfortable than most spiders living among humans. They don't seem to be bothered by us.
DAVIS: I've seen them on gas station pumps, streetlamps. I've even seen some on the top of streetlights in the middle of a busy intersection downtown. I mean, that's actually crazy to me.
MATHENY: They also weave very durable webs.
DAVIS: The Joro webs are so strong that a bird can actually land on them, stay there and then fly off.
MATHENY: Given how prolific Joro spiders are at reproducing, they're likely to expand across the country. For one, they travel well, hitching rides on cars and trucks, Davis says.
DAVIS: I know one was spotted in Baltimore. There's been one in sort of West Virginia. I talked to a student who was here at UGA who accidentally transported one to Oklahoma.
MATHENY: So Joro spiders may soon show up in a backyard near you if they aren't there already. For NPR News, I'm Martin Matheny in Athens, Ga. Transcript provided by NPR, Copyright NPR.
NPR transcripts are created on a rush deadline by an NPR contractor. This text may not be in its final form and may be updated or revised in the future. Accuracy and availability may vary. The authoritative record of NPR’s programming is the audio record.
