Golden webs stretched across porches, walking paths and even the University of Tennessee campus are becoming a familiar late-summer sight in Knoxville, and the culprit is an eye-catching invasive spider that has now firmly settled into the city, not just the surrounding Smoky Mountains. The Joro spider, native to parts of Asia, has been spotted throughout Knoxville and inside Great Smoky Mountains National Park as its population spreads across East Tennessee.
According to the Knoxville News Sentinel, iNaturalist has recorded 1,294 Joro spider sightings in Tennessee, with 1,241 of those confirmed and 53 observations still awaiting identification. The app shows several sightings clustered around Knoxville specifically, and officials are asking residents who spot one to photograph it, upload it to iNaturalist, and email the image to [email protected].
Recent sightings mapped by the paper include spiders at The Hill on UT's Knoxville campus, along Circle Drive on August 11, and at a cluster confirmed on James White Parkway on September 7. Joro spiders have also turned up at the Knoxville Botanical Garden and Arboretum, at Ijams Nature Center in August, and around Bearden, off Papermill Drive, and in West Hills, the outlet reports. The species has now spread beyond Tennessee into Alabama, North and South Carolina, and across the broader Southeast since it was first detected in Georgia in 2014, per the same account.
What The Webs Look Like And Why They're Everywhere
Female Joro spiders are easy to identify by their black-and-yellow markings, while males are smaller and dull brown, maturing earlier, by August, compared with females, who mature in late September and early October after hatching in early June, according to the Knoxville News Sentinel. Their three-dimensional golden silk webs can stretch up to 10 feet wide and are often built at eye level across walking paths, porches and outdoor shelters, according to The Cool Down.
Part of why the spiders seem to be everywhere at once comes down to how they travel. Juvenile Joro spiders disperse over long distances through a process called ballooning, releasing fine silk strands that catch atmospheric winds and even Earth's electrostatic currents, while adult spiders cannot fly, as reported by WBIR. University of Tennessee entomologist Karen Vail emphasized that these ballooning spiderlings are only about the size of a sesame seed.
Should Knoxville Residents Be Worried?
Despite their intimidating size, Joro spiders rarely bite people or pets, and researchers describe them as venomous but nonaggressive, per the Knoxville News Sentinel. When bites do occur, they typically cause only mild stinging or redness. Experts recommend not killing the spiders on sight, since they're easily mistaken for native orb-weavers that play a similar role in local ecosystems.
Researchers believe the species was accidentally introduced to the U.S. through shipping containers and potted plant materials from its native range, which includes China, India, Japan, North Korea, South Korea, Taiwan and Vietnam. A 2023 modeling study led by Clemson University researchers found that Joro spiders could colonize most of the eastern United States, after evaluating 20 environmental variables and determining that North American conditions closely match their native East Asian habitat, according to Clemson University.
What The Spiders Mean For Native Species
Per iNaturalist, Joro spiders are believed to be linked to local declines in native orb-weaver populations, though the exact reason behind those declines remains unknown. Great Smoky Mountains National Park logged its first confirmed Joro spider sighting inside its boundaries in October 2024, when an AmeriCorps volunteer photographed one in the Cades Cove area, an incident that Backpacker notes.
University of Tennessee graduate student Caitlin Jones is now conducting field surveys inside the park to determine whether Joro spiders are actively displacing native orb-weaving species, according to CBS News. Federal regulations prohibit park visitors from disturbing or harming wildlife within the boundaries, which limits how the public can respond to sightings there.
Newer research offers some reassurance on that front. A University of Georgia study using DNA analysis of gut contents found that Joro spiders eat small flies, per 11Alive. That finding pushes back against earlier ecological models that feared the spiders would monopolize local insect prey, though the Knoxville News Sentinel notes the overall environmental impact of the species is still not yet known.
An Unexpectedly Chill Neighbor
Beyond diet, the spiders have some habits that make them oddly suited to city life. A University of Georgia study found that Joro spiders tolerate high urban noise and traffic vibrations, helping explain why their webs so often appear along busy roadways, according to UGA Today. Separate research from the University of Georgia found that when disturbed, Joro spiders display a startle response and remain frozen rather than acting aggressively, per UGA Extension.
There's also a potential upside for gardeners: ecological observations show Joro spiders readily capture and eat brown marmorated stink bugs, an invasive agricultural pest that native spiders rarely touch, according to Wikipedia. And research from the University of Georgia found the spiders maintain a high metabolic rate in cold temperatures, letting them endure brief freezes compared with golden silk spiders, which helps explain why their activity persists into late autumn across East Tennessee.
Knoxville's Joro spike follows a broader northward creep the species has made in recent years. Joro sightings have reached as far north as Massachusetts, as Hoodline previously reported, underscoring how far the golden orb-weavers have already traveled from their first Georgia detection in 2014.
