A large, brightly colored invasive species called the Joro spider is on the move in the United States. Populations have been growing in parts of the South and East Coast for years, and many researchers think it's only a matter of time before they spread to much of the continental U.S. But spider experts say we shouldn’t be too worried about them.
The Joro spider is one of a group of spiders called orb-weavers, named for their wheel-shaped webs. They're native to East Asia, have bright yellow and black coloring and can grow as long as three inches when their legs are fully extended. However, they’re pretty hard to spot at this time of year because they’re still early in their life cycle, only about the size of a grain of rice.
Scientists are still trying to figure that out, said David Coyle, an assistant professor at Clemson University who worked with Nelsen on a study on the Joro's range, published last November. Their central population is primarily in Atlanta but expanding to the Carolinas and southeastern Tennessee. A satellite population has taken hold in Baltimore over the last two years, Coyle said.
Joro spiders will eat whatever lands in their web, which mainly ends up being insects. That could mean they'll compete with native spiders for food, but it might not all be bad — a Joro's daily catch could also feed native bird species, something Andy Davis, a research scientist at the University of Georgia, has personally documented.