(Forsyth County, GA) After a brief winter hiatus, Joro spiders are once again out and about and likely spreading farther through the United States than ever before.
Joro spiders, scientifically known as Trichonephila clavata, are a spider species native to Japan as well as Korea, Taiwan, and China. The first Joro spider sighting in the United States was in Hoschton, Georgia in 2013, and they have since spread predominantly across northern Georgia and western South Carolina.
The first Joro spider sightings in the southeast were close to highways and interstates suggesting these spiders likely made their way to the United States hidden away on shipping containers. Researchers believe they are continuing this same hitchhiking process on trucks and cars, spreading them farther distances and at a quicker rate than they naturally would.
Joro spiders are very easy to spot. They have bright yellow and dark blue stripes along their backs with red markings on their abdomens. Not to mention these colorful arachnids span nearly 3 inches across from leg to leg.
But even if you do not happen to spot the spiders themselves, their webs leave quite the impression as well. Joro webs, some spanning several meters in length, are large, three-dimensional webs that shine a golden yellow in the sunlight and tend to be suspended higher than other native spiders.
A New Home
Andy Davis, a research scientist at the University of Georgia’s Odum School of Ecology, says there is much still to be learned about Joro spiders and how they fit into new ecosystems in the United States.
“It might take multiple studies over many years to really figure it out,” said Davis.
Davis says this is normal citing decades of research for other introduced species such as Cane toads and kudzu. But unlike some introduced species which go on to harm their new ecosystems, known as invasive species, early research suggests the docile nature of the Joro spiders makes them at worst neutral to their surrounding environments.
In fact, Joro spiders may even be a net positive as they likely provide another food source for local species, such as birds, and have been observed catching nuisance insects as well as Brown marmorated stink bugs, an invasive species known to seriously damage crops and seek shelter in homes and buildings during the winter.
Joro spiders are predicted to be here to stay as they become naturalized to U.S. environments. And while researchers will ultimately have to wait and see, it is anticipated Joros will spread farther across the U.S. because of climates similar to their origins.
“If you look at that northern part of Japan, their climate is very similar to that of the New England area. [But] that’s just an educated guess,” Davis said. It is the same line of thought for warmer climates in the west too. “It’s another educated guess. If they can make it out there, they’ll probably do pretty well.”
Joro spiders spread by employing a common technique of orb-weaving spiders called ballooning. Ballooning is when a spider climbs to somewhere high, stands on raised legs, and shoots a little parachute of webs from its spinneret that allows the wind to carry the spider, sometimes for miles.
For some people, this paints a picture of giant spiders flying through the air, but this is not the case.
“[After] the mama spider lays her eggs at the end of the fall, in the spring they hatch. And then once the spider legs get big enough they send up a little silk thread that carries them to a new spot,” Davis said. “You never see this happening because the spiders are like the size of a pencil head.”
So while the new generation of Joro spiders has already hatched, many of them are still so small they require a keen eye to be seen. By late summer and early fall, the big Joros and even bigger webs will be back.
What Should You Do About Joro spiders?
So what does this all mean for you? For most people, not much, really. The newness of the Joro spider paired with its eye-catching colors and impressive webs have caused a frenzy among the media and locals, many of whom go to great lengths to kill them.
This is not only harmful to the Joro population but to many native spider species as well. “The Joro-mania has taken hold, and I think people are going to start killing everything. That’s very unfortunate,” Davis said.
And while entomologists like Davis urge people to largely leave them alone, the number of Joro spiders and their webs can sometimes reach impractical levels. Cindy Heard, the founder of Forsyth Exterminating, works to help maintain a balance so that Joros can live without your house being engulfed in their webs.
Forsyth Exterminating’s approach to ridding your house of Joros, as well many other kinds of spider, is to eliminate their sources of food, such as mosquitos, through periodical treatments to deter the spiders into another area.
“I would say a good program every month just to help control them,” Heard said. However, if the prevalence continues to be too much despite this, exterminators will go to the point source and destroy the Joro’s egg sacks which hold somewhere between 400 to 1500 eggs each.
While much is still to be learned about Joro spiders, their docile nature is well documented. They spin webs in trees, bushes, and attach to structures but seem to have no interest in entering houses or buildings. While it may be necessary to remove webs that are in the way, entomologists like Davis implore people not to kill Joros when they are doing no harm.
Regardless, many residents like Cindy still have their reservations about Georgia’s newest arachnid.
“It's very intimidating because of the size of it. I'm terrified of them. They're very intimidating, and I do not want one of them on me,” Heard said.
But Davis says you can use them as an educational opportunity for yourself and your kids. “There's very few other creatures in the natural world that will just do their thing right in front of you for four months.”
Davis suggests throwing food, like flies, into the webs to see the Joro in action, but he says even just observing it in its natural habitat for a while can help quell the fears many adults and their children have about spiders.
The fear of spiders is one of the most common phobias, but Davis says it does not have to be that way.
“Arachnophobia is a learned thing you kind of learn from your parents,” Davis said. “I have two sons, six and eleven, and neither of them are afraid of spiders. That’s probably because I’m not.”
So while the jury is still out on how exactly the Joro spider fits in with us and our surrounding ecosystem, one thing is for certain: the Joro spider is here to stay.
If you have a news tip in Forsyth County, contact Ben Lacina at benjaminclacina@gmail.com
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