The Joro spider has arrived in Pennsylvania, just in time for the Halloween festivities.

Reports indicate that six of these large, vividly colored spiders, first identified in Georgia nearly ten years ago, were seen in Bucks County, near Philadelphia on September 5, as per Joro Watch, a monitoring project initiated by the University of Georgia’s Center for Invasive Species and Ecosystem Health.

Bucks County is located 43 miles away from Philadelphia.

Following the report, a local entomologist visited the site to confirm the sighting, according to the Bucks County Courier Times, part of the YSL News NETWORK. This observation has also been validated by a researcher and EDDMapS Data Coordinator from the University of Georgia.

What are Joro spiders?

The Joro spider, an invasive species from East Asian countries like Japan, Korea, Taiwan, and China, is thought to have originally arrived in the U.S. in the early 2010s. Its scientific name is Trichonephila clavata.

Females of this species are notably larger, measuring around 3 to 4 inches, and are characterized by their yellow bodies with dark blue stripes and red abdomens. In contrast, males are smaller, just over a quarter of an inch long, brown, with dark gray or black and yellow stripes.

These spiders prefer sunny environments and do not typically reside indoors. They belong to a category of large spiders called golden orb-web weavers, which are known for constructing large, intricate webs made from a gold-colored silk, as noted by the University of Georgia.

They are capable of “ballooning,” which involves using their silk to float through the air to new locations, earning them the nickname “flying” spider. Joro spiders can create webs that can reach widths of up to 10 feet.

Where have Joro spiders been spotted in the U.S.?

By 2022, Joro spiders had spread across approximately 120,000 kilometers in the U.S., primarily in Georgia, South Carolina, North Carolina, and Tennessee, with sightings reported in Alabama, Maryland, Oklahoma, and West Virginia, based on a study by researchers at Clemson University.

The research indicated that these spiders are rapidly moving beyond South Carolina and have the potential to thrive throughout much of the eastern U.S.

David Coyle, a scientist and professor at Clemson, noted a significant finding from the study: “These creatures are here to stay.”

Coyle emphasized that the findings showed that their preferred habitats in their native regions align closely with large areas of North America, suggesting that “this spider will likely be able to inhabit most of the eastern U.S.”

Are Joro spiders harmful?

Although the size of Joro spiders may be off-putting, they are quite gentle and pose no real threat to humans, dogs, or cats. They possess venom but typically do not bite unless threatened, and their fangs are not strong enough to penetrate human skin.

According to entomologist Nancy Hinkle from the University of Georgia, Joro spiders also play a beneficial role in “pest control,” as they feed on insects such as mosquitoes, flies, and stink bugs. Birds will eat these spiders as well; however, the overall impact on the Southeastern ecosystem and its species is still being studied.

Contributors: Jo Ciavaglia, Amanda Wallace, Bucks County Courier Times