Researchers at the University of Georgia say the Joro spider, an invasive species native to east Asia, is expected to spread across the US east coast after thriving in Georgia last year.
The spider, scientifically known as Trichonephila clavata, has the ability to spin highly organized, wheel-shaped webs. Female spiders have blue, yellow and red markings and can measure up to three inches when fully extended.
Joro spider has relatives already in the US
Researchers found that the Joro has double the metabolism of its relative, aka the golden silk spider, which moved to the US southeast from the tropics 160 years ago. Unlike the golden silk spider, which has been unable to spread north due to its inability to withstand cold temperatures, the Joro has a 77% higher heart rate, meaning it can survive freezes that kill off its cousins.
Joro spiders, which predominantly hail from Japan, will probably survive on the US east coast because Japan has a very similar climate and is located approximately on the same latitude, researchers said in a new study released on March 3.
“Just by looking at that, it looks like the Joros could probably survive throughout most of the eastern seaboard here, which is pretty sobering,” said Andy Davis, a research scientist at the Odum School of Ecology and co-author of the study.
Last year, the spiders made their way through the yards of northern Georgia, spinning webs up to three yards deep.
It is unclear how the spiders traveled from east Asia but researchers say their proliferation is probably due to changes in weather conditions.
The Joro does not appear to have much of an impact on local food webs or ecosystems and may even serve as an additional food source for native predators, such as birds, researchers said.
“People should try to learn to live with them,” Davis said. “If they’re literally in your way, I can see taking a web down and moving them to the side, but they’re just going to be back next year.”
“The way I see it, there’s no point in excess cruelty where it’s not needed,” Benjamin Frick, co-author of the study and an undergraduate researcher in the School of Ecology, said. “You have people with saltwater guns shooting them out of the trees and things like that, and that’s really just unnecessary.”
Some researchers believe humans will help the spiders spread.
“The potential for these spiders to spread through people’s movements is very high,” Frick said. “Anecdotally, right before we published this study, we got a report from a grad student at UGA who had accidentally transported one of these to Oklahoma.”
The chances of a Joro spider climbing into a car or into luggage is quite high but researchers stress that there is no reason to panic. Even though the spiders can bite, they are not a threat to humans as their fangs are often not large enough to puncture human skin.
“There’s really no reason to go around actively squishing them,” Frick said. “Humans are at the root of their invasion. Don’t blame the Joro spider.”