PENNSYLVANIA, USA — A venomous spider from thousands of miles away is nearing Pennsylvania.
"We're not entirely sure how they got to North America in the first place from Asia," said Michael Skvarla, assistant research professor of arthropod identification and the head of the Insect Identification Laboratory at Penn State.
Skvarla says the Joro spider, a native of Southeast Asia, was first spotted in Georgia a decade ago and has since spread north to the Carolinas.
"Joro spiders are going to be really distinctive amongst spiders in our area. They're going to be the largest web building for orb-weaving spiders," he said. "They have about a four-inch legspan. The body is kind of this neon green and grey striped pattern. There's really nothing else that looks like it."
While it may appear Joro spiders can fly, Skvarla said they're not really flying. Baby spiders climb up to the tops of trees and jump off, releasing a small piece of silk and floating off to different destinations, a process called ballooning.
Skvarla said all sorts of spiders are pretty much raining down on you through the spring and summer months, you just can't see them. They're small enough to fit on the point of a ballpoint pen.
If Joro spiders make it to Pennsylvania, it won't be by ballooning. Skvarla said Joro spiders only migrate about ten miles per year on their own, but their sacks of eggs can attach to vehicles or moving containers.
"They could be here this year, they could be here in five years, they could be here in ten years," he said. "It's just going to be a matter of somebody accidentally moving them and the population getting going from there."
If Pennsylvania does see them, they're relatively harmless to humans. Joro spiders keep to themselves but can bite in self-defense.
Skvarla said it's as painful as a bee sting and Joro venom is very weak.
"We shouldn't panic," he said. "They probably will be here eventually. They are big spiders, but they aren't threatening spiders. There's no reason to worry about them."
Skvarla said Joro spiders prefer warmer climates, so the Keystone State may be the northernmost migration point for these colorful crawlers.