The giant Joro spiders are expanding on the East Coast this summer: What to know

Written by on June 6, 2024


(NEW YORK) — New York City and New Jersey might have a new resident this summer: A giant yellow and blue-black flying spider.

The creepy crawler — the Joro spider — has stirred up a frenzy over a possible invasion in the tri-state area.

What is a Joro spider?

Also known as the Trichonephila clavata, the Joro spider is from east Asia and can grow to the size of a palm.

Female Joro spiders are typically yellow with legs that can grow up to four inches. Male Joro spiders aren’t nearly as big and are a blue-black color.

Besides their striking appearance, Joro spiders are also known for their web-weaving abilities.

Mature female Joro spiders can spin yellow or golden webs that are extremely strong, while spaning up to 10 feet, according to a study by University of Georgia’s Department of Entomology.

Joro spiders are able thrive in urban environments, which is one of the reasons they have been able to migrate northward in the United States.

The spiders “have the ability to thrive everywhere,” David Coyle, who focuses on Forest Health and Invasive Species at Clemson University, told ABC News.

Where did the Joro spider originate from?

The Joro spiders originated from east Asia and are native to Japan, Korea, Taiwan and China. While it is unknown how the spider arrived in the U.S., scientists speculate the spider likely arrived through international cargo.

The arachnid made its first appearance in Georgia over a decade ago. They’ve also been seen in Maryland, Oklahoma, Alabama, Tennessee, North Carolina, West Virginia and South Carolina, according to iNaturalist, which has tracked where they’ve been spotted.

iNaturalist is a site where individuals submit findings of plants and animals and get help with identifying them, this is a tool some scientists use in their research.

Can Joro spiders fly?

The short answer is no.

However, Joro spiders are light enough to parachute through the air, traveling with the speed of wind, giving the illusion they are flying through a process of “ballooning.”

Ballooning is when the spiders make “silk webs that act as a parachute, it lifts them into the atmosphere and carries them into the air,” Michael J. Raupp, a professor who specializes in entomology studies at the University of Maryland, told ABC News.

Another way they have been able to spread is by hitchhiking onto cars or other items transported by humans.

Are Joro spiders dangerous?

While the spider has been referenced as venomous, Joro spiders are not dangerous, according to a study by Dr. Andy Davis at the University of Georgia.

Most spiders are venomous, but a bite from Joro is not deadly, researchers concluded.

When threatened, Joro spiders will play dead for around a minute but can stay motionless for as long as an hour, according to a study by the University of Georgia.

Joro spiders are actually shy and gentle and don’t pose a threat to humans or pets, said Davis.

Are Joro spiders invasive?

Any non-native species has the potential to disrupt the biodiversity of an area, in the case of the Joro spider it can cause a downsize in food for native spiders in the area, according to Raupp.

Some scientists remain unsure of what impact Joro spiders can have on an area’s ecosystem.

“Joro spider is not in the category as the spotted lanternfly,” said Davis.

In 2022, scients encouraged people to squish spotted lanternflies when they saw one, because they were disrupting the ecosystem by feeding off of a wide range of plants.

However, the Joro spider can bring some benefits. 

“Joro spiders can be incredibly important in reducing pests,” Raupp told ABC News.

When can we expect to see Joro spiders?

While they have been spotted as far north as Maryland, it is still not certain the tri-state area in the northeast will see the Joro spider this summer.

Joro spiders can parachute to travel north but the ballooning process has less of a chance for survival. In the air, the spiders can’t control where they end up, stated Coyle.

“The ability to live [in the northeast] is being interchanged with the ability to get there,” said Coyle.

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