Professor Requests Public's Help to Track Invasive Jorō Spiders in Maryland
Baltimore & Eastern Shore residents asked to help Washington College spot and record species’ expanding population.
Angela Chuang, assistant professor of environmental science and studies and biology has issued a public call to action for residents in the Baltimore area and on the Eastern Shore to help track the expansion of the Jorō spider (Trichonephila clavata), an invasive species that up until recently had only been seen in large numbers in the U.S. in parts of Georgia, Tennessee, and South Carolina. The spiders are large and can sometimes be confused with yellow garden spiders because of their similar size and coloring. Yellow garden spiders are native to Maryland.
Chuang is currently the only researcher studying this distinct, emerging population in the Northeast, which was first documented near Elkridge, Maryland, in 2022. She needs citizen scientists to photograph and report sightings using the popular iNaturalist app to understand how quickly and broadly the species is spreading in the Mid-Atlantic.
New Invasion Provides Critical Research Opportunity
The Jorō spider, a large, brightly yellow and black colored orb-weaver native to Asia, is currently most visible as adult females reach their maximum size, often with a leg span up to four inches, in the late fall. Chuang’s research at Washington College focuses on the ecological impact of this new arrival.
“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.”
Because much of the work around studying Jorō spiders in the U.S. has been done in the South so far, and due to climate differences, Chuang notes that the population dynamics can be expected to be different in terms of when they’re out in the year, and in terms of how they interact with other native species.
“We’ve found that just because competition or something is happening with native spiders in the South, it doesn’t guarantee it will happen here. That’s part of my interest and what I’m hoping to do here,” said Chuang.
Her chief concern remains the species’ effect on local wildlife. “I am very interested in studying this new local population to determine if Jorō spiders are having a negative impact on native spider communities. We have observed them quickly becoming the most numerous spider species within a few short years of them arriving to new sites, which is characteristic of other invasive species.”
Not a Threat to Humans
The Jorō spider may look imposing, but Chuang’s prior research, conducted while she was a postdoctoral researcher at Clemson University, found that the species is not considered a health or safety threat to humans or pets.
In an interview with Clemson on her work, Chuang said that no danger was found and even when bitten, subjects had little to no reaction to bites.
“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.
Public Asked to Become Citizen Researchers
The best way for the public to assist Chuang and the wider scientific community is to use the iNaturalist app, a free, widely-used citizen science platform. iNaturalist connects users to a community of scientists and naturalists who can help identify uploaded findings. The data collected by the app is essential for tracking biodiversity and the movement of species like the Jorō spider.
How to Report a Jorō Spider Sighting:
- Get the App: Download the free iNaturalist app on your smartphone (available for iOS and Android) and create an account.
- Take a Photo: When you spot a Jorō spider (look for the bright yellow, blue, and red coloring and large webs, often in urban areas or on the edges of forests), open the app and select "Observe" to take a clear photograph.
- Upload & Locate: The app automatically logs the date, time, and GPS location of your observation.
- Identify: Enter your identification as "Jorō Spider" or simply "Spider." The iNaturalist community will help confirm the sighting, turning your photo into scientifically useful data that Chuang and her colleagues can use to map the species growth and expansion.
The public is encouraged to check for the spiders now, as the conspicuously large females are visible until late November or early December, depending on the weather.
Chuang is also looking for opportunities to study these spiders in the wild. Baltimore and Eastern Shore residents can email her directly at [email protected] to send photos of their findings and invite her team to come study them. She is interested in pursuing field verification of new locations.
To learn more about Chuang’s work and other research happening in Washington College’s Biology department visit their webpage.
- Dominique Ellis Falcon