Before you squash a Joro spider, you might want to take a closer look.
The large yellow arachnid meeting its doom might not be the invasive species popping up across Northeast Georgia, but a native spider of similar size and color.
Mattias Johansson — assistant professor of biology at the University of North Georgia Gainesville campus who specializes in invasive species research — said Joro spiders are often confused with the writing spider, also known as the yellow garden spider, which is prevalent throughout the area. People also tend to mix up the arachnid with the banana spider, which is less common in the region.
Johansson said the tell-tale for a Joro spider lies with its web.
“Joro’s webs are three-dimensional and often big,” he said. “The webs are also yellow.”
Contrastingly, he said the writing spider builds a “traditional web” with one layer. The strands exhibit a white color and little characteristic zigzags.
The way the Joro and writing spiders position their legs additionally helps with deciphering between the two. Johansson said writing spiders often hold their front pair of legs together and back pair of legs together, forming an “X” shape with their bodies. The Joro spider prefers to keep its limbs separated.
Johansson advises against only looking at the spider’s color, patterns and legs to determine the difference between a Joro and writing spider. Patterns can vary within the same species and the yellow arachnids can exhibit different sizes depending on their stage of life.
Johansson said some people will say that the Joro has striped legs, and the writing does not. However, that isn’t always the case.
“There are writing spiders with stripey legs and there are Joro spiders with just solid-colored legs,” Johansson said. “Webs are the most obvious difference and the way the writing spiders make an “X,” where the Joros hardly ever do.”
Garrett Hibbs — Hall County cooperative extension agent who has been monitoring the invasive arachnid — said unfortunately for banana spiders, they have a similar yellow, multi-layered web like the Joro.
“One way to distinguish between the two is the banana spider’s hairy legs,” Hibbs said. “The bottle brush legs, that’s one thing you can be confident about.”
If people feel comfortable enough to peer closely, Hibbs said the splash of red on a Joro spider’s abdomen also helps it stand apart from the others.
Over the past year, Johansson has examined a few unknowns about the Joro spider, including its effect on native wildlife. From what he’s gathered in the area, he said the arachnids seem to be “replacing the writing spiders” by moving into their natural habitat, on the edge of forests.
“That’s the problem with invasive species,” he said. “They don’t just eat other things. One of the reasons we think the Joros are displacing the writing spiders is they seem to like similar locations.”