Palm-Sized Spiders Could Make Their Way To PA This Summer, Experts Say

PENNSYLVANIA - The Joro spider, a Post-It Note-sized arachnid that has burgeoned in southern U.S. states since 2021, is slated to make its debut in Pennsylvania as soon as this summer, according to multiple reports.

The species, which is native to East Asia, can grow as large as the size of a human palm and craft wheel-shaped webs; females are brightly colored with red, blue and yellow hues while males are brown. While the spider’s venom doesn’t pose a danger to humans or pets, its sheer “unusually large” size can be frightening alone - and may soon be terrifying arachnophobic Pennsylvanians.

Per a 2023 study conducted by David Coyle, a scientist and assistant professor in the Department of Forestry and Environmental Conservation at Clemson University, Joro spiders are "here to stay" in the states and are spreading like wildfire.

“Those data show that this spider is going to be able to inhabit most of the eastern U.S.,” Coyle said. “It shows that their comfort area in their native range matches up very well with much of North America.”

The spiders have been spotted as close as Maryland last October.

“Soon enough, possibly even next year, they should be in New Jersey and New York,” José Ramírez-Garofalo, an ecologist and Ph.D. candidate at Rutgers University, told SILive.com last December.

The species uses wind currents to travel while parachuting, a method of silk production that allows the spiders to travel in the wind. If northern winds and spiderling births align, it could mean a Joro spider spread to northern states as soon as this summer.

The Mid-Atlantic states would make sense as a next destination for the spiders as the region is the same latitude as places in Asia where they thrive. The species can can survive a brief freeze that kills off other spiders and has about double the metabolism of its relatives, according to one study.

It is “only a matter of time” before Joro spiders head to New York and New Jersey, University of Georgia research scientist Andy Davis told The New York Times last year.