These aren’t early Halloween decorations: giant ones Joro Spiders, known for skydiving into the air, were spotted in Pennsylvania this month.
Six of these spiders were reported on September 5, according to Joro Watch, an interactive monitoring program developed by the Center for Invasive Species and Ecosystem Health at the University of Georgia. An entomologist went to Bucks County, Pennsylvania, and verified that there were adult Joro spiders.
What are Joro spiders?
Joro spiders, an invasive species native to Asia, can shoot long silk threads that are carried by the wind and carried through the air. Some have called them parachute spiders because of the way they move.
According to PennState Extension, they create large webs that can be up to 10 feet wide.
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Adult females are large and brightly colored, with legs up to 4 inches long, experts say. Males are much smaller. While female Joro spiders are about 1 inch long, male Joro spiders have a body length of less than ½ inch.
Female Joro spiders, known for their yellow and gray abdomens, lay egg sacs containing 400 to 500 eggs.
The spread of Joro spiders: where are they going?
Joro spiders were first discovered Joro spiders were discovered in Georgia in 2014, but experts believe the invasive species may have arrived as early as 2010. Joro spiders have spread throughout the South in the years since. They have now been reported in more than a half-dozen states.
In 2022, PennState Extension said it was likely that Joro spiders “could spread throughout eastern North America, at least to Pennsylvania and perhaps further into warmer coastal areas.” Researchers thought it might take 35 years for Joro spiders to reach southeastern Pennsylvania, but said there were two ways Joro spiders could reach Pennsylvania faster.
One possibility is that young, small Joro spiders are carried tens or even hundreds of kilometers through the air after being blown away by strong winds and storms. The other possibility is that they are transported to new areas by humans.
José R. Ramírez-Garofalo, an ecologist at Rutgers University’s Lockwood Lab and president of Protectors of Pine Oak Woods in Staten Island, told SI Live in April that “it’s a question of when, not if” the spiders will arrive in New York and New Jersey.
Are Joro Spiders Dangerous?
Joro spiders do have venom, but it is weak. They also have small fangs, making it difficult for them to pierce human skin.
“We have no evidence that they have caused any harm to any person or pet,” said the Clemson University assistant professor. Dave Coylewho holds a doctorate in entomology, previously said.
If a bite does occur, PennState Extension said it is less painful than a bee sting and any localized pain and redness would quickly disappear.
