Large, invasive Joro spiders are crawling across the East Coast

Giant, venomous yellow spiders have been making their way up the East Coast, and people could start seeing them in New Jersey, New York and even southern Canada as soon as this year.

The invasive Joro spider, native to East Asia, was first found in Georgia in 2013. The spiders mostly stay in the Southeast, but researchers predict they will head north as they are better adapted to colder climates.

The creatures are characterized by their bright colors and large size. Female Joro spiders are yellow and black, with bodies the size of a paperclip and legs that can extend up to 4 inches from side to side. Male Joro spiders are smaller and brown. They are orb weavers, meaning they create flat, circular webs.

Joro spiders have recently attracted attention on social media, but experts say there is nothing to worry about. Almost all spiders are venomous, including these ones, but only a tiny fraction have venom that could seriously harm a human, said Gustavo Hormiga, a biology professor at George Washington University.

He compared a Joro spider bite to a bee sting. Some people may have a bad reaction, but Hormiga said he has yet to hear of any cases that would be considered medically significant.

He described the spiders as “very shy”.

“They have no interest in biting you,” Hormiga said, so they would probably only do it in self-defense.

Still, people may want to watch out for the spiders’ large webs: A single Joro spider can be 3 feet wide, but a cluster web containing several females can span 10 feet.

Andy Davis, a researcher at the University of Georgia’s Odum School of Ecology, said the Joro spider’s larger relatives are fried “like shrimp” and sold as a snack at street markets in Asia from ballast.

Joro spiders can survive in a wide range of conditions, he added.

“Joro spiders seem perfectly content living on a gas station pump in addition to living in a tree in the forest,” he said.

Davis said spiders respond to stressors like noise differently than other spiders he has studied. In his lab, Davis tested the spider for “shyness” by directing a small puff of air toward it. The spider Joro responded by freezing for an hour. On the other hand, many other animals would react more, making it difficult for them to live in a stressful environment in the long term.

But Joro spiders’ lack of reaction allows them to establish webs in surprising places, such as at traffic lights above busy intersections, Davis said.

“If they can live in these disturbed areas as much as they can live in natural areas, that means there’s nothing stopping them from living anywhere in this country,” he said.

There is no way to predict exactly when the spiders will arrive in the Northeast, since their movement is random, said David Nelsen, an arachnologist and biology professor at Southern Adventist University in Tennessee.

“Because they have the color and the size and that element of fear, they’re really, really exciting,” Nelsen said, although guessing that “New Yorkers won’t see that anytime soon.”

Although stories have circulated about the spiders taking flight, Nelson said they are mostly misinterpreted. Adults don’t do this, he said, but baby Joro spiders have the ability to balloon, an action Nelsen likens to dandelion seeds being picked up by the wind. Like seeds, spiders disperse randomly depending on wind and electromagnetic currents.

“Spiders as tall as commercial airplanes, 30,000 feet in the air, have been reported,” Nelsen said.

According to Davis, Joro spiders of all ages can also hitch a ride in a car, without the driver knowing, and end up in a new state.

Being relatively harmless to humans does not entirely eliminate the spider threat. They are invasive and Nelson’s research has shown that when large numbers of Joro spiders live in an area for a long time, native spider populations decline.

“A lot of evidence suggests that when an ecosystem loses species, which can happen in this case, that ecosystem really, really gets lost and can collapse. »

Nelsen said, however, that more research was needed to determine whether Joro spiders were behind the decline.

For now, Hormiga said, the spiders pose no scientifically documented problems for their local environment. But it will take years for scientists to understand their long-term effects.

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