People up and down the entire US east coast may soon find themselves living with a large spider species that is a long way from its original home.
According to researchers at the University of Georgia, the Joro spider, an invasive species native to east Asia, is expected to spread after thriving in the state last year.
The spider, Trichonephila clavata, is known for its ability to spin highly organized, wheel-shaped webs. Females have blue, yellow and red markings and can measure up to 3in when fully extended.
Researchers found that the Joro has double the metabolism of a relative, the golden silk spider, which moved to the US south-east 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 and can thus survive freezes that kill off its cousins.
According to the new study, 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.
“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 3m deep.
It is unclear how the spiders traveled from east Asia but researchers say their proliferation is probably due to changes in weather conditions.
According to Davis, 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 like birds.
“People should try to learn to live with them,” he 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.”
Benjamin Frick, co-author of the study and an undergraduate researcher in the School of Ecology, said: “The way I see it, there’s no point in excess cruelty where it’s not needed. You have people with saltwater guns shooting them out of the trees and things like that, and that’s really just unnecessary.”
Frick believes humans will help the spiders spread, saying: “The potential for these spiders to spread through people’s movements is very high … 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. Although 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.”
