What you need to know about the giant, 'flying' spiders spreading over the eastern US

A black-and-yellow Joro spider in a web
Joro spiders are an invasive species in the US, but they aren't as scary as they seem.David Madison/Getty Images
  • Get ready for flying spiders the size of your palm. They could be coming to your neighborhood soon.

  • Joro spiders have been rapidly spreading across the southeast US, and are now moving north.

  • Though venomous, Joro spiders aren't harmful to humans and prefer to stay outdoors.

It sounds like the stuff of nightmares: venomous, monster-sized spiders floating through the air and invading the northeastern US this summer.

But some experts say invasive fruit flies can do more damage than the colorful Joro spider, AP News reported.

It's easy to understand why the spider sounds terrifying, though.

They can measure up to 3 inches with their legs spread, about the size of your palm and far larger than a quarter-inch house spider.

Giant spiders migrating to the Northeast US

Sugarloaf Mountain from the scenic lookout at the Top of the 80's restaurant in Hazleton, Pennsylvania.
Scientists say Joro spiders are adapted to colder climates like in Pennsylvania and New Jersey.Cheri Sundra--Guerrilla Historian/Getty Images

Originally native to Asia, they've been rapidly moving across the southeast US since first appearing in Georgia around 2010, according to a study published last year in the journal Ecology and Evolution.

And the invasive species has been heading north, according to the study's authors. Once they arrive, people are likely to spot their webs — a distinctive golden color — in trees or on their porches, according to UGA Today.

"This spider is going to be able to inhabit most of the eastern US," David Coyle, a professor at Clemson University who worked on the research, told Clemson News in 2023 adding that "their comfort area in their native range matches up very well with much of North America."

Colder temperatures don't seem to bother them. The black-and-yellow spiders survive just fine in northern Honshu, Japan, where winter temperatures can reach between 25 and 32 degrees Fahrenheit, according to Penn State Extension.

"Barring some unforeseen circumstance, we expect the range of these things to continue expanding, likely to the north, and we've already seen that with some populations in Maryland," Coyle added.

Experts from NJ Pest Control predict that the spiders could arrive in New Jersey and New York this year, potentially as soon as this summer.

"It's not a matter of if, it's a matter of when," Russell Sieb, an entomologist and the owner of NJ Pest Control told Business Insider.

"They are going to make it up to the northeast at some point, and we think that they're going to be up here sometime this year," he said, adding that they've already been spotted in Baltimore.

A shy spider who prefers the outdoors

A yellow, black, and red Joro spider in a web
While Joro spiders are invasive, their full impact on ecosystems in the US isn't yet known.Alex Sanz/AP Photo

Though the massive creatures are venomous, they aren't dangerous to humans beyond potentially causing a swollen, red bite, Sieb told BI. And they don't want to take a nibble out of you, anyway.

"They aren't looking to bite things they can't eat if they can help it," Jonathan Larson, University of Kentucky entomologist, said in 2022.

They're also not a danger to pets, and researchers have found they may be the "shyest" spiders ever documented.

Beyond their size, there's another characteristic of Joro spiders that makes them a little creepy: They can fly. Well, kind of.

'Flying' Joro spiders

Joro spider in its web
Joro spiders can travel far by using their silk as a wind-sail. It's similar to flying.Jean-Philippe Tournut/Getty Images

The orb-weaving arachnids don't have wings, but they can travel by "ballooning," a technique where they release a strand of silk that allows the wind to carry them. Sieb said they can travel around 3 miles using this method.

Luckily for arachnophobes though, Joro spiders typically don't want to go inside homes — they're outdoor pests that usually opt to form webs in open spaces like parks, ball fields, or suburban properties, though they may also seek out wooded areas or the doorways to buildings, Sieb said.

And, although the species is invasive, you probably won't be fighting off bazillions of them right and left.

"It's not going to be like any Alfred Hitchcock movie or anything like that with them all over the place," Sieb said.

Though they do live close to each other, Joro spiders don't seem to interact much with other individuals, per UGA Cooperative Extension.

"This is a predator," Sieb told BI. "So there's going to be a carrying capacity for the area. So you might have two on a property maybe, or not even two."

Just how these spiders will impact the ecosystems they invade is still an open question. Joro spiders love to eat another invasive species, lanternflies. However, there's no chance the spiders will help eradicate the plant-eating pest, per AP News.

"A lot of people think that this spider is destroying the ecosystem, and we actually don't think that, at least not yet," Andy Davis, an assistant research scientist at the University of Georgia, told UGA News.

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