EASTERN SHORE, Md. - A biologist at Washington College in Chestertown is calling on Eastern Shore residents to help track sightings of large, bright yellow arachnids native to East Asia as they spread on the East Coast.
The Joro spider is a species of orb-weaver spiders known for their meticulous wheel-shaped webs. Female Joro spiders are a colorful yellow with blue and red markings on their bodies. Fully grown, the females can reach three inches across with their legs extended.
The spiders began making national headlines in recent years due to their ability to “balloon,” releasing silk threads into the air to be carried off by the wind. The mode of transportation has allowed them to spread rapidly in some parts of the United States, including Georgia, Tennessee, and South Carolina.
Now, researchers are hoping to discover how much that spread has reached our part of Maryland.
Initially, the spiders were thought to be limited to the south due to climate. Recent research, however, suggests the spiders are better suited to colder temperatures than related species, with higher metabolisms and heart rates that allow them to survive brief freezes.
The spiders are also found throughout much of Japan, which, unfortunately for arachnophobes, has a similar climate.
Angela Chuang, an assistant professor of environmental science and biology researching the Joro’s spread in the Mid-Atlantic, is asking that anyone who witnesses the flying yellow spiders to document the sightings.
“The main thing is, we would like it if people could report when they see these spiders, so we have a better understanding of how Jorō spiders are spreading around, especially because this is a distinct population from the older one,” said Chuang. “It represents an opportunity to study an invasive population at its earliest stages.”
Chuang says she is studying how the spiders are impacting local wildlife, especially their potential negative impacts on Maryland’s native spiders. Joros have quickly become the most numerous spider species within just years after their appearance, according to Chuang. They were first documented in Maryland in Elkridge in 2022.
Despite their intimidatingly large size, Chuang says the spiders are not a threat to humans or pets. During her previous research, Chuang said she found even their bites caused little to no reaction.
“We hope these studies teach people some of the dos and don’ts around managing these spiders and go a long way towards alleviating any personal safety and health concerns around them,” she said.
Chuang asks Eastern Shore residents who may run into a Joro to photograph it and report it with the iNaturalist app. She is also looking for opportunities to study the spiders in the wild, and invites Baltimore and Eastern Shore residents to send her photos directly at JoroSpidersWC@gmail.com to alert her team of local sightings.