Joro spider is big, but fear not, says UGA researcher

'I don't think this species deserves to be squished'

The Joro spider, a large spider native to East Asia, is seen in Johns Creek, Ga., on Oct. 24, 2021. Researchers say the large spider that proliferated in Georgia in 2021 could spread to much of the East Coast. (AP Photo/Alex Sanz)
The Joro spider, a large spider native to East Asia, is seen in Johns Creek, Ga., on Oct. 24, 2021. Researchers say the large spider that proliferated in Georgia in 2021 could spread to much of the East Coast. (AP Photo/Alex Sanz)

The idea of palm-sized airborne spiders sweeping from Georgia up the East Coast has attracted a lot of media buzz. But Andy Davis, the University of Georgia scientist whose recent study started it all, said people shouldn't really be so concerned.

Davis generally studies animal physiology but got the idea to take a closer look at Joro spiders because they were all over his backyard in Athens, he said in a phone interview. Davis wondered if the palm-sized spider's physiology would allow it to spread to colder climates up the East Coast.

He discovered that they could, but wanted to clarify that Joro spiders are airborne only when they're babies seeking new territory. According to iNaturalist, a citizen scientist website, there have been four sightings of the Joro spider in the Chattanooga area, Davis found, and none in Northwest Georgia. Several Northwest Georgia agricultural extension agents also reported no sightings, despite the Joro spider, which arrived in the state in 2013, having found a solid foothold in Athens and Atlanta.

"Females will grow throughout the summer and fall, then they'll lay some eggs before they die. They'll die in November when the cold comes," Davis said. "In the spring the eggs will hatch. The little babies will send up their parachute thingies - it's like a little silk thread - and they'll fly away. It won't be until the summer, when the spiders get big enough, for people to start seeing them."

All spiders are venomous - they must have venom to subdue their prey, wrote Nancy Hinkle, professor in the Department of Entomology at the University of Georgia College of Agricultural and Environmental Sciences, in an email. But Joro venom is not toxic to humans. Instead, it is designed to be effective against insects, Hinkle wrote. Other research from the University of Georgia indicates that the Joro spider won't bite unless it's cornered, and its fangs are generally not large enough to break human skin.

(READ MORE: Asian spider takes hold in Georgia, sends humans scurrying)

Will Hudson, a University of Georgia Extension entomologist, said in an email that the Joro spiders pose no real threat to the public. They certainly are invasive in the sense they're here without invitation, he wrote, but they seem to have little effect on the overall ecosystem or other spiders so far.

Davis agreed the Joro spider hasn't crowded out any native species, but it has been seen eating brown marmorated stink bugs, which are from the spider's native range. That is a good thing, he said, because no native spiders eat them. Some scientists are hoping, Davis said, that the Joro spider could migrate to the Northeast and eat the destructive spotted lantern fly - because it is also from the same region in Eastern Asia as the Joro.

(READ MORE: Five invasive species we should be eating, plus recipes from locals)

Published in the scientific journal Physiological Entomology, the study compares the Joro spider to the golden silk spider, its relative. The golden silk spider migrated to the Southeast about 160 years ago but hasn't spread any further. The study found the Joro spider has a significantly higher heart and metabolic rate than the gold silk spider - as well as a higher tolerance to freezing temperatures - which Davis and co-author Benjamin L. Frick theorize will allow it to survive cold weather found outside the Southeast.

Davis said invasive insects like the Joro spider are a sign of the times. With global commerce and shipments crisscrossing the globe, that kind of thing is happening all the time, he said. The Joro spider isn't dangerous to anyone, just a nuisance, he said. The webs are everywhere when they reach maturity between August and October - on back porches, sheds, trees and bushes. Despite being harmless, Davis said the Joro spider will forever change walking in the woods because they spin their webs about eye height.

The Joro spider hasn't been reported in Walker, Catoosa or Bartow counties, according to Wade Hutcheson, county extension agent in Walker County in a phone interview. He said the Joro spider is "a good hitchhiker" and has mainly been spreading up the Interstate 85 corridor.

When it comes to invasive species, he said he's mostly worried about English ivy, the Callery pear and the Asian longhorn tick. Found in Tennessee and Gilmer County, Georgia, last fall, the tick can reproduce asexually and can lay up to 2,000 eggs at a time, as opposed to native ticks that lay a clutch of just about 200.

"And with wildlife or livestock, they're preferred hosts, they can even cause death due to [ex]sanguination, blood loss, because there's so many ticks on them," Hutcheson said.

At the end of his interview with the Times Free Press, Davis said he hoped this article would avoid the "fear-mongering spin" that leads to fear and spider squishing.

"I don't think this species deserves to be squished. It might be in your way, but people could just move it aside," he said. "It's not really its fault it's here. It was literally just along for the ride."

Contact Andrew Wilkins at awilkins@timesfreepress.com or 423-757-6659. Follow him on Twitter @tweetatwilkins.

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