Joro spiders, giant, venomous flying arachnids, are here to stay, pest experts say

Giant venomous flying spiders with 4-inch legs are real, and they're going to potentially invade the New York area sometime this year, according to the New Jersey Pest Control.

Joro spiders are coming to the Northeast after initially infiltrating the Southeastern U.S. from Japan, the pest control service said in a news release earlier this year. Georgia served as the "ground zero" for the arachnids in 2021 as residents saw the spiders in urban and rural areas, WUGA, the University of Georgia's public FM radio station, reported.

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The Japanese spider is "hard to miss " due to its "striking appearance and distinct behavior," according to the Flanders, New Jersey-based pest control service. The spiders are a "vibrant yellow" and have black coloration, the extermination service's release said.

What makes the Joro spider different from other spiders is its ability to fly by using a technique called "ballooning," the pest control service said. Ballooning involves the spider releasing silk threads into the air, which allows them to be carried by the wind, according to the release.

How did Joro spiders come to America?

The theory behind the Joro spiders' origin in the U.S. is that the venomous arachnids were unintentionally transported by way of cargo shipments, international trade and personal travel, the New Jersey Pest Control said.

It is unclear exactly how they got to America, but the "consequences of their arrival are becoming increasingly evident," according to the pest control service.

The Joro spiders’ ability to adapt to various environments and reproduce rapidly led to them successfully establishing the Southeast as its initial epicenter, the pest control service said.

“This spider is going to be able to inhabit most of the eastern U.S.,” David Coyle, invasive species expert at the University of Clemson, said in October 2023. “It shows that their comfort area in their native range matches up very well with much of North America... Barring some unforeseen circumstance, we expect the range of these things to continue expanding, likely to the north, and we’ve already seen that with some populations in Maryland."

José R. Ramírez-Garofalo, an ecologist at Rutgers University's Lockwood Lab, told the Staten Island Advance in April that "it is a matter of when, (and) not if" the spiders make their way to New York and New Jersey.

How will Joro spiders affect local ecosystems?

The introduction of the Joro spiders can "disrupt the delicate balance of local ecosystems," according to the exterminators.

When in their native habitats, which are within the borders of Southeast Asia, Joro spiders control insect populations because they act as "natural pest controllers," the pest control service said.

"The Joro spider’s predatory nature may decrease native insect populations, affecting the food web and potentially causing a ripple effect throughout the ecosystem," according to the exterminators.

For humans, particularly residents and local authorities, Joro spiders could cause "fear and apprehension" due to the intimidating appearance of the arachnids, the pest control service said. The Joro spiders' venom is typically not deadly to humans, but when bit, it can cause discomfort and allergic reactions in some people, according to the release.

How to get rid of the Joro spiders?

The Joro spiders seem to be here to stay, so there are not any definitive ways to get rid of them.

"In the face of the unprecedented Joro spider invasion, communities must unite, educate, and adapt," the pest control service said. "The delicate balance of ecosystems requires a nuanced understanding of these arachnids, emphasizing coexistence and responsible management. As we conclude, let us remember the importance of harmonizing with nature to foster resilient and sustainable ecosystems."

People who encounter Joro spiders can call their local pest control services to exterminate them from their homes or property. Aside from extermination, the public's options are limited as entomologists and ecologists continue to study the colorful creatures' migration to America.