These aren’t early Halloween decorations: This month, giant Joro spiders, known for parachuting through the air, were spotted in Pennsylvania.
Six of the spiders were reported on Sept. 5, according to Joro Watch, an interactive monitoring program developed by the University of Georgia’s Center for Invasive Species and Ecosystem Health. An entomologist visited Bucks County, Pennsylvania, and confirmed that adult Joro spiders were present.
What are Joro spiders?
Joro spiders, an invasive species native to Asia, can shoot long strands of silk that are caught by the wind and carried through the air. Some call them parachuting spiders because of the way they move.
According to PennState Extension, they build large webs that can be up to 10 feet (3 meters) 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 an inch long, male Joro spiders have a body length of less than a half inch.
Female Joro spiders, known for their yellow-gray abdomen, lay egg sacs containing 400 to 500 eggs.
The Distribution of Joro Spiders – Where Are They Going?
Joro spiders were first found in the US in Georgia in 2014, but experts believe the invasive species arrived as early as 2010. Joro spiders have since spread across the South. 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 through eastern North America, at least to Pennsylvania and possibly farther into warmer coastal areas.” Researchers there had thought it could take 35 years for Joro spiders to reach southeastern Pennsylvania, but said there were two ways Joro spiders could reach Pennsylvania more quickly.
One of these was when young and small Joro spiders were transported tens to hundreds of kilometers through the air after being picked up by strong winds and storms. The other way would be when they were 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 on Staten Island, told SI Live in April that “it’s a matter of when, not if” the spiders arrive in New York and New Jersey.
Are Joro spiders dangerous?
Although Joro spiders do have venom, their venom is weak. They also have small fangs, making it difficult to pierce human skin.
“We have no evidence that they caused harm to a person or a pet,” said an assistant professor at Clemson University. Dave Coylewho has a doctorate in entomology, said earlier.
If someone bites you, it is less painful than a bee sting, according to PennState Extension, and any local pain and redness disappears quickly.
