Spider Invasion
Big, invasive Joro spiders are crawling up the East Coast
Experts predict they may soon appear in New Jersey, New York, and even southern Canada.
The East Coast of the United States is bracing for an unusual invasion this summer. The intruders are not soldiers or immigrants but rather giant, vibrant yellow spiders known as Joro spiders. These arachnids, native to East Asia, have been making their way across the Southeastern states since their first U.S. appearance in Georgia around 2013.
Characterized by their striking color and impressive size, female Joro spiders are yellow and black, with a body roughly the size of a paperclip and legs that can extend up to four inches. Males, on the other hand, are smaller and brown. Both are orb weavers, creating flat, circular webs that can span up to 10 feet.
Despite their intimidating appearance, Joro spiders pose no significant threat to humans. According to Gustavo Hormiga, a biology professor at George Washington University, their bite is akin to a bee sting. While some people may have adverse reactions, there have been no medically important cases reported. Hormiga also emphasized their shy nature, explaining that they would only bite in self-defense.
The Joro spider's rapid spread has raised concerns about its potential impact on local ecosystems. David Coyle, an assistant professor of forest health and invasive species at Clemson University, reported that Joro spiders had become ubiquitous in their native range. Using modeling techniques, Coyle and his team assessed the Joro spider's range and then applied it to the entire U.S. The data revealed that the Joro spider's comfort zone in their native range aligns well with much of North America. "Barring some unforeseen circumstance, we expect the range of these things to continue expanding, likely to the north," Coyle stated.
Joro spiders have gained notoriety for their ability to fly through the air using a ballooning method. This unique trait has significantly contributed to their rapid expansion across the Southeastern states and now threatens to push them farther north. However, David Nelsen, an arachnologist and biology professor at Southern Adventist University in Tennessee, clarified that only baby Joro spiders can balloon, dispersing randomly based on wind and electromagnetic currents. Reports of Joro spiders at high altitudes, such as commercial airplanes, are likely misconceptions.
The arrival of Joro spiders in the U.S. is believed to have occurred accidentally through cargo shipments and international trade. Their rapid reproduction and adaptability to different environments have made them a formidable invasive species. In their native Japan, Joro spiders colonize most of the country. Japan has a very similar climate to the U.S. and is approximately the same latitude. This similarity suggests that Joro spiders could probably survive throughout most of the Eastern Seaboard.
Despite their alarming spread, some experts argue that Joro spiders may not be as harmful to ecosystems as initially feared. While there is evidence that these spiders displace native species, their overall impact remains a subject of ongoing research. Andy Davis, a research scientist at the Odum School of Ecology at the University of Georgia, shared that larger relatives of the Joro spider are consumed as a snack in East Asia. He also noted their adaptability to various living conditions, from gas station pumps to forested areas.
Davis further explained that Joro spiders react differently to stressors than other spiders he has studied. When exposed to a small puff of air, a Joro spider will freeze for an hour, while many other animals would react more, making it challenging for them to survive in stressful environments long term. However, this lack of reaction allows Joro spiders to set up webs in unexpected places, such as on traffic lights above busy intersections.
For now, the public is advised to be aware of these spiders but not to panic, as they do not pose a significant threat to humans or animals. The focus remains on monitoring and managing the spiders' spread to mitigate their impact on both human populations and local wildlife. As they are expected to expand, understanding and coexistence will be crucial in addressing the challenges posed by these striking yet unsettling invaders.
In conclusion, the East Coast is gearing up for a double invasion this summer, with both cicadas and Joro spiders making their presence known. While the cicadas' emergence is a natural phenomenon, the Joro spiders' arrival is a reminder of the ever-changing biosphere and the importance of staying informed about the natural world around us.