Joro spiders, those scary-looking critters that can apparently fly through the air when their giant webs are lifted by the wind, have been making big headlines in recent weeks — mainly because of predictions that the creepy crawlers might make their way into New Jersey, New York or Pennsylvania as early as this summer.
While the news may send shivers up the spine of people who get the willies just thinking about spiders, experts say there’s nothing to worry about. They say there’s no evidence the Joro spiders have moved anywhere close to our region of the country, and even if they did, it could take years for them to get established and multiply in big numbers.
On top of that, even though these spiders are venomous, experts say the level of toxins they would transmit if they bit a human would be very small and likely harmless.
Whether or not that eases your fear, here are several facts about Joro spiders, also known as “parachuting spiders.”
What are Joro spiders?
This 8-legged critter (which is a type of arthropod, so it’s technically not an insect) has the scientific name of Trichonephila clavata. It belongs to a group of spiders known as “orb weavers” because they can spin highly organized webs shaped like a wheel.
The males are small, but the females are much larger, with bright yellow markings. When fully grown, the female spider’s body can grow up to an inch long and its legs — which are black with yellow stripes — can span up to 3 to 4 inches. So stretched out, its diameter can be as large as a human palm.
“Adult male Joro spiders are much smaller and duller in color compared to females, with a body length of only 0.3 inches,” the Penn State Extension notes. The males are typically light brown, with lateral stripes that are dark brown.
Why are they called Joro spiders?
This spider got its name from a mythological creature — a Japanese spider demon known as Jorogumo.
Why are they called parachuting spiders?
The Joro spider is known for spinning large, intricate, wheel-shaped webs — some as wide as 10 feet — that can be lifted into the air by gusts of wind. Researchers say this allows these pests to travel to different locations miles away, make new colonies, multiply, then move again to other locations.
The process of the webs flying through the air is commonly known as ballooning, and sometimes called kiting.
Where did Joro spiders originate?
Experts say the Joro spider is native to China, India, Japan, North Korea, South Korea, Taiwan and Vietnam. Its first confirmed sighting in the United States was in northern Georgia in 2013 or 2014. Researchers believe the spider likely hitched a ride on a shipping container or a potted plant that originated from Asia.
Which states have these spiders?
Experts say the Joro spider has been seen in large numbers in northern Georgia and has spread to areas of Alabama, North Carolina, South Carolina and Tennessee during the past few years. One Joro spider was found in Oklahoma, but it didn’t get there by flying through the air on a web. It reportedly traveled in a car with a graduate student from the University of Georgia.
Recent sightings have been reported as far north as Maryland and West Virginia. But as of early June, there have been no confirmed sightings of Joro spiders in New Jersey, New York, Pennsylvania or Delaware.
Will Joro spiders spread to northern states?
Researchers from the University of Georgia released a study in February 2022 saying Joro spiders can tolerate cold temperatures, so they may eventually make their way up and down the eastern United States — including northern states.
“It’s inevitable. We’re going to get them,” Russ Sieb, owner of NJ Pest Control, based in northern New Jersey, told NJ Advance Media in early June 2024. “It’s not a matter of if, it’s a matter of when.”
When will the spiders arrive here?
No one knows for sure. Some experts say it likely will take several years for the Joro spiders to make their way up to Delaware, New Jersey, Pennsylvania or New York through natural means and perhaps as long as five to 10 years to get up to New England. However, they note these spiders might be able to spread to northern states much sooner than that if they hitch a ride on cars, trucks or shipping containers — or if they get carried by the winds of a strong storm.
Experts from the Penn State Extension say these spiders have been spreading only about 10 miles per year since they first arrived in Georgia. “At that rate, they may reach southeastern Pennsylvania in 35 years and northwestern Pennsylvania in 60 years” by natural means, the Penn State Extension says. “However, spiderlings (baby spiders) are capable of moving tens to hundreds of miles via ballooning, so a storm blowing in the right direction at the right time of year may move them in large jumps.”
The Penn State Extension also notes the spiders’ arrival time in northern states could be pushed up by “accidental human transport.”
During recent weeks, some experts predicted the Joro spiders could start to appear in northern states like New York and New Jersey as early as this summer. Others said it’s more likely to happen later in 2024.
Can Joro spiders survive harsh winters?
Experts say it’s not known for certain whether Joro spiders or their eggs can survive long, harsh winters. But the researchers in Georgia determined the Joro is more likely than similar types of spiders to survive brief periods of freezing temperatures.
They also said these spiders are able to create colonies and thrive in most areas of Japan, which “has a very similar climate to the U.S. and is approximately the same latitude.”
“It looks like the Joros could probably survive throughout most of the Eastern Seaboard here, which is pretty sobering,” Andy Davis, one of the researchers, said.
Can Joro spiders hurt people or animals?
Because they have tiny fangs and are not known to be aggressive, Joro spiders “are relatively harmless to people and pets, making their presence more of a nuisance than dangerous,” according to a report by the University of Georgia. “Joros won’t bite unless cornered, and their fangs are often not large enough to break human skin.”
If a person happens to get bit by a Joro spider, they may get localized redness and swelling, Sieb said. “If you happen to be allergic, hypersensitive to things, then you might have a bigger reaction.”
Can Joro spiders harm trees or plants?
At this time, experts say there’s no evidence Joro spiders will cause damage to trees or plants. They seem to be merely an aesthetic annoyance because they spin huge webs that can stretch across landscaping, porches, lawn furniture and power lines.
What do Joro spiders eat?
Joro spiders tend to eat various insects, including stink bugs, yellow jackets and mosquitoes, and they also feed on other types of arthropods, such as lady beetles (better known as ladybugs).
Michael Raupp, an entomologist from the University of Maryland, says Joro spiders will also feed on a pest that has been threatening grapevines, other agricultural crops and some types of trees in New Jersey and other eastern states during the past several years — the spotted lanternfly.
So that may be one good thing about these scary-looking spiders.
Note: Parts of this report were originally published in March 2022 and have been updated for this report.
Stories by Len Melisurgo
- N.J. weather: Severe thunderstorm watch issued for 8 counties, with strong storms possible
- Giant ‘flying’ Joro spiders could soon invade N.J., N.Y. and Pa., experts say
- Live election results: U.S. Senate, House races in N.J. primary elections 2024
Thank you for relying on us to provide the local news you can trust. Please consider supporting NJ.com with a voluntary subscription.
Len Melisurgo may be reached at LMelisurgo@njadvancemedia.com or on X at @LensReality.
If you purchase a product or register for an account through a link on our site, we may receive compensation. By using this site, you consent to our User Agreement and agree that your clicks, interactions, and personal information may be collected, recorded, and/or stored by us and social media and other third-party partners in accordance with our Privacy Policy.
