Flying Joro Spiders Heading for the East Coast — Everything to Know

The spotlight for the “bug of the summer” has certainly been on spotted lanternflies and cicadas over the last few years. Now, it’s time to prepare for Joro spiders! According to a CBS report, the northeast U.S. is bracing for an invasion of the large, flying spider.

Experts have been warning of the incoming invasion of the Joro spider since 2022, and the New Jersey Pest Control said in early 2024 that they would be “hard to miss” as they make their way into more states. Females have a leg span of up to 4 inches and are known for their vibrant yellow and grey bodies.

The giant Joro spiders, sometimes called “parachuting spiders,” are set apart from other spiders through their ability to fly, a trait uncommon among spiders. These arachnids use a technique known as “ballooning,” where they release silk threads into the air, allowing them to be carried by the wind.

Ahead, learn all there is to know about Joro spiders.

What Is an Invasive Species?

The Joro spider is an invasive species, aka an organism that is not indigenous to a particular area and is likely to cause economic and environmental harm to the new area.

Native to East Asian countries such as Japan, Korea, Taiwan and China, Joro spiders are thought to have arrived in the United States through cargo ships and personal travel, according to USA Today. Since then, they have spread across Georgia, Tennessee and into the Carolinas, with sightings in Maryland, and as far west as Oklahoma, according to a study by Clemson University.

With the seasons transitioning from spring to summer, the spiders are expected to reproduce and spread to other states.

How To Identify Joro Spiders?

Joro spiders are easily identified by their larger size and distinctive yellow and grey color pattern.

Due to their size, they may be intimidating in appearance, but they likely won’t arrive in numbers large enough to threaten any native species valuable to the environment. They build large webs between power lines, easy to spot in the morning when speckled with dew, on top of traffic lights, poles along busy roads, and even above gas pumps. While females are brightly colored (they have yellow and gray abdomens), males are brown.

How Big Are Joro Spiders?

Some Joro spiders can measure as large as eight inches in length, so these summer visitors will be fairly easy to spot in and around your property.

Joro spiders have a body about four inches long and legs that span six to eight inches, around the size of the human hand. The females can grow to an inch long and 2 to 3 inches across with their legs outstretched.

Are Joro Spiders Dangerous?

The size of a Joro spider can be startling, but the real nuisance might be the large webs that people could walk into by mistake! Joro spiders are considered timid creatures (their bite is comparable to the sting of a bee). Because of their small mouth parts, they are usually not a safety concern for humans, who they will not bite unless provoked.

They will eat virtually any creature they can snare on their web, but they are not a threat to agriculture. Dr. Daniel Kiefer, PhD Entomologist and Technical Manager at American Pest says, “Spiders get a bad reputation, but they are actually beneficial to controlling other insects in your yard. Joro spider venom is reserved for their prey, which humans and pets are most certainly not.”

You need not worry about the Joro spiders getting inside your home. They want to build their webs and do their circus-like flying outside. “Our technicians use special dewebbing brushes to clear visible webs on the outside of your home, which will be the most effective way to keep them from accidentally getting inside. Flying is dramatic, but, like in Charlotte’s Web, it’s mainly for the Joro spiders to get from one area to another.”

About the Expert

• Dr. Daniel Kiefer, PhD, is an entomologist and technical manager at American Pest

Sources

• MDPI: “How Urban-Tolerant Are They? Testing PreyCapture Behavior of Introduced Jor Spiders (Trichonephila clavata) Next to Busy Roads
• CBS: “Joro spiders are an invasive species known for parachuting through the air. Here’s why you shouldn’t fear them.”
• USA Today: “Joro spiders, giant, venomous flying arachnids, are here to stay, pest experts say”
• Clemson.edu: “Clemson scientist: Study shows Joro spiders ‘here to stay,’ spreading fast”
• National Geographic: “Invasive Species”

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