Since their arrival in Georgia nearly 10 years ago, the yellow-banded Joro spiders and their huge webs have set up camp in the southeastern U.S., experts say.
A new study from Clemson University indicates they’re “here to stay.” But they’re harmless to humans.
The spiders were discovered in Georgia in 2014 and have taken root in the U.S., according to an Oct. 12 release from the university.
The creatures travel via a unique mechanism called “ ballooning,” according to Penn State University. They use gossamer threads to catch the wind and sail on air currents to a new location.
Researchers say their bodies can grow about an inch long, with their legs spanning up to four inches. The females are larger and brighter in color than the males.
The spiders’ spread
David Coyle, a professor of forest health and invasive species at Clemson, said he’s seen the population of Joro spiders on his South Carolina property “explode” over the last few years, according to the release.
Coyle worked on the study with other researchers, using 20 variables to model how the Joro spider would fare in the U.S. given its typical native habitat in East Asia.
“Those data show that this spider is going to be able to inhabit most of the eastern U.S.,” Coyle said in the release. “It shows that their comfort area in their native range matches up very well with much of North America.”
Their current range spans over 46,000 square miles in states including Georgia, South Carolina, North Carolina and Tennessee, according to the release.
Joros have also been reported in Alabama, Maryland, Oklahoma and West Virginia.
Another study has shown the Joro spider to be more cold-resistant than its relative, the golden silk spider, allowing Joros to spread farther north.
University of Georgia entomologist Will Hudson also began investigating the spiders after seeing them in his yard.
“Last year, there were dozens of spiders, and they began to be something of a nuisance when I was doing yard work,” Hudson said in 2021. “This year, I have several hundred, and they actually make the place look spooky with all the messy webs — like a scene out of ‘Arachnophobia.’”
Impact
Despite their size and abilities to soar through the air, Joro spiders don’t hurt people. In one study, UGA scientists even found they are pretty shy.
“Yes they can look big, and yes some people are quite afraid of spiders, but the reality is there’s really no dangers these pose to people or pets,” Coyle said.
Researchers are still working to understand the spiders’ impact. Coyle said they can look at metrics such as whether other varieties of spiders are less common in areas where Joro spiders are found.
“I think people need to make peace with Joros and accept the spiders because they are not going anywhere,” Richard Hoebeke, who first identified the spiders in 2014, told UGA.
For now, the spiders don’t appear to have an adverse impact on native species, UGA reported. And you don’t have to kill the spider if you see it.
If you see a spider and you don’t want it there, Coyle recommends getting a broom and moving it.
