The Joros are Here – and They’re Not Leaving

The Joros have moved in to Georgia. No, they’re not the family next-door, but a species of spider who probably arrived by hitching a ride in a shipping container from China, Korea or Japan and landing in Hoschton, Georgia, back in 2013. Their identities were confirmed by the University of Georgia College of Agricultural and Environmental Sciences Department of Entomology based on genetic analysis in 2015.

Now, five years later, Joro spiders appear to have successfully established themselves in the area, with recent confirmed reports around residential properties in Barrow, Jackson and Madison counties, and  from as far as Blairsville and Greenville, S.C. That means the golden orb-weaving spider has colonized effectively.

Although there is still much that remains unknown about them, here are some things we do know:

• At more than 3 inches across when their legs are fully extended, they’re roughly the same size as banana spiders and yellow garden spiders.
• The distinctive yellow and blue-black stripes on their backs and bright red markings on their undersides are unique.
• Their enormous three-dimensional webs are a striking golden color and tend to be located higher off the ground than those of other spiders.
• Joros seem to be really common in riparian areas and in urban areas around people’s houses, but they’re also in the deep woods.
• Early observations indicate that Joros are coexisting with the area’s other orb weaving spiders, with webs close to, and in some cases even attached to, one another.
• September through late November is when they are most actively building webs. The female matures in September and is nearing the end of her year-long lifespan by late November.

Joro spiders also appear to be able to capture and feed on at least one insect that other local spiders are not: adult brown marmorated stink bugs, an invasive pest that can infest houses and damage crops. In turn, Joro spiders are vulnerable to predators like mud dauber wasps and birds.

Further genetic analysis is being conducted to determine what causes some Joro spiders to have a different color pattern. While most have distinctive black and yellow striped legs, some have legs that are solid black. These black morphs have other physical differences that are only apparent when viewed under a microscope, and they are genetically distinct members of the species.

Despite their tremendous size, Joro spiders don’t pose a threat to people.  If you disturb their web, they’ll probably run from you; they’re trying to get out of the way. Joros are not deadly, but a bite from one can really hurt.

Have you encountered Joro spiders at your home? Contact a pest control expert to evaluate the issue.