Could Flying Joro Spiders Be Headed to Pennsylvania?

Pennsylvania might soon be home to a new kind of spider that’s causing quite a buzz — the Joro spider. Originally from East Asia, these vibrant, large spiders have been making their way across the southeastern United States. Given their ability to “fly” using their webs, there’s now speculation that they could soon reach Pennsylvania.

What Are Joro Spiders?

Joro spiders, which are native to East Asia, first appeared in the U.S. in Georgia in 2014. It’s believed they arrived via shipping containers, and they have since spread rapidly. These spiders have established themselves in states like Georgia, South Carolina, North Carolina, and Tennessee, and there have even been sightings in Maryland and West Virginia.

Could They Survive in Pennsylvania?

According to a 2022 study by Penn State Extension, it’s quite possible. The Joro spider thrives in environments similar to those found in Pennsylvania.

For instance, in northern Honshu, Japan, where these spiders are native, January temperatures range between 25 and 32 degrees Fahrenheit — conditions that are quite comparable to Pennsylvania’s winter climate. This adaptability suggests that they could indeed survive and spread throughout Pennsylvania.

What Do They Look Like?

Joro spiders are quite striking in appearance, especially the females. Adult females have bodies that are about one inch long and a leg span that can reach up to four inches.

They are brightly colored, with a yellow and gray-blue abdomen and a red mark underneath. Their legs are black with yellow bands. In contrast, the males are much smaller and less colorful, with body lengths of about 0.3 inches.

How Do They Fly?

Joro spiders use a fascinating technique known as “ballooning” to travel. They produce silk threads that catch the wind, allowing them to float through the air and cover long distances. This ability has greatly contributed to their rapid spread across the southeastern U.S.

Are They Dangerous?

Despite their size and ability to “fly,” Joro spiders are not a threat to humans or pets. Their venom is weak, and they are generally reluctant to bite. Even if they do, their fangs are usually too small to penetrate human skin. Essentially, these spiders pose no real danger to people.

What Impact Could They Have?

The arrival of Joro spiders could have mixed effects on local ecosystems. On the plus side, they might help control pest populations, such as mosquitoes and stink bugs. However, there is concern that they could compete with native spider species for food and habitat, potentially disrupting the local ecological balance.

What’s Next?

Experts believe that Joro spiders will continue their northward expansion, potentially reaching Pennsylvania in the coming years. Their spread is driven by both natural dispersal mechanisms like ballooning and accidental human transport.

Although their immediate arrival in Pennsylvania is not certain, the likelihood increases each year as they continue to expand their range.

For now, the best approach is to stay informed and not to panic. Doug Tallamy, an entomologist at the University of Delaware, suggests that while the possibility of Joro spiders arriving is real, it’s “very low on the list of things we should be worried about.”

What to Do If You See a Joro Spider

If you encounter a Joro spider, there’s no need to be alarmed. These spiders prefer the outdoors and are unlikely to enter homes. If you need to move one, simply use a broom or a stick to relocate it safely.

While their presence might be startling at first, Joro spiders are just another species adapting to new environments. Their expansion into the U.S. is a testament to the incredible adaptability of nature.

Leave a Comment