Joro spiders spotted in Pennsylvania: Fact vs. fiction about the arachnids

The giant, parachuting spiders known as Joro spiders, are starting to spread from the southeastern United States and have made an appearance in a suburb of Philadelphia.

There was a sighting earlier in September in Bucks County, according to JoroWatch.org.

Experts have said they could arrive in New York and New Jersey this summer.

But how much do we need to really be concerned about them?

The Joro spider has a leg span of up to four inches and can fly...well, sort of. It can move great distances by releasing silk threads into the air and parachuting around using the wind.

Giant, parachuting Joro spiders expected to arrive in NY and NJ this summer

The creepy crawlers aren’t native to the U.S., coming to the area from Asia in recent years. And while they are indeed venomous, they do not pose any real risk to humans and pets.

So how worried should tri-state residents be? Here's an answer to some frequently asked questions and concerns.

Will the Joro spiders really invade the northeast in a rapid manner this year?

Basically, the spiders won't be getting to the New York and New Jersey area on their own. They move the quickest by getting a ride on something else.

"They’re hitchhikers, so it all depends how they get here," said Russell Sieb, owner of NJ Pest in Flanders. "They got here from Asia through containers."

The northeast does get shipments from the southeast, so the spiders will likely hitch rides on those as they come north.

But just how quickly will they arrive? That's much tougher to tell.

Will you find the spiders inside your home?

Sieb says the spiders likely won’t seek shelter in your home and shouldn’t strike fear in humans.

What do Joro spiders eat?

Here's where some people may warm up to the spiders a bit. While they are an invasive species themselves, they will do some good to as they weed out a different invasive pest.

Joro spiders will pretty much eat any insect that gets trapped in its web — which includes the spotted lanternfly.

"The spotted lantern fly, when they came in they were truly invasive, no predators. But the Joro spider is a predator, so it’ll eat other insects," said Sieb.

But how much of an impact it will have on the region's ecosystem is still a mystery.

Are Joro spiders dangerous?

While Joro spiders may appear frightening to some, they are relatively harmless to people and pets, a University of Georgia study from earlier this year said. In fact, that study found that Joro spiders may be the shyest spider ever documented.

The spiders will only bite if they're cornered and even then their fangs likely wouldn't be large enough to pierce human skin, according to the University of Georgia study.

Another positive about the spiders: they don't want to go inside homes, according to Coyle. They will instead spin webs on the outside of houses or other structures. If a Joro spider needs to be moved, Coyle suggests using a broom or stick to place it elsewhere.