Invasive Joro Spiders Sighted in New York and Delaware, Experts Urge Calm

As summer ushers in the warm weather, so do the sizeable Joro spiders, originally from Asia, but now making their presence known in the United States. These arachnids, with females growing up to three to four inches with vibrant yellow bodies streaked with black, often weave extensive gold-toned webs that are hard to miss.

The invasive Joro spiders have been spreading since their first sighting in the United States approximately a decade ago in Georgia. Experts anticipate sightings to expand further up the East Coast in the coming years.

Residents of New York and Delaware might encounter these unexpected arachnids, but should not be alarmed. Despite their intimidating appearance, Joro spiders are relatively harmless and pose no significant danger to humans.

About 60 nonnative spider species have been identified in North America, with the Joro spider being one of the latest additions. Their ability to hitch rides on various commodities due to their secretive behavior has facilitated their spread.

Since their initial appearance in North America in 2014, Joro spiders have managed to establish populations in north-central and northeast Georgia, extending into neighboring regions of Tennessee and South Carolina. They have made their presence felt between Forsyth, GA, and Baltimore, with a rare sighting even in Oklahoma in 2021.

Studies conducted by researchers at the University of Georgia suggest that the Joro spider’s cold tolerance makes their northward expansion highly likely, given the ample suitable habitat present that supports their successful invasion.

Richard Hoebeke, an associate curator at the University of Georgia Collection of Arthropods, has highlighted the Joro spider’s relatively benign nature, with few reported instances of them biting humans. Caution is advised when encountering these spiders, but they generally pose no threat.

While the Joro spider genus is proficient at ballooning, a behavior observed in many spider species, their success in new environments has raised concerns about potential displacement of native species. Studies have shown conflicting results, with some experts suggesting that native spiders may be excluded from areas with a high Joro spider presence.

Despite differing opinions on the impact of Joro spiders on local ecosystems, some residents in Georgia have embraced these arachnids, even establishing online communities to appreciate the captivating new neighbors.