For residents of the Southern United States, fall marks the return of joro spiders – large, bright yellow arachnids that appear in Asia-hauning borders, gardens, and almost anywhere large enough to throw large webs.
JORO SHOULD NOT make big threats to people. But their abundance seems to be a source of great ire for local residents – something David Coyle, an entomologist at Clemson University, as South Carolina’s state consultant on invasive species.
After years of cleaning complaints related to Joro, Coyle and his team decided to formally investigate these questions – long years leading to two studies dealing with Joro spiders, on October 22, in the Journal of Medical Entomology and the economic journal.
Gizmodo talked coyle about spiders and shared tips for dealing with unwanted joro encounters. The following discussion has been slightly edited for grammar and clarity.
Gayoung Lee, Gizmodo: What are Joro spiders, and why are they considered invasive?
David Coyle: Jro spiders are native to China and parts of Asia. They first arrived in the US around 2010 but were first discovered in 2014 in North Georgia. Since then, they have spread to many states, all the way up in the northeast. There are people from Baltimore and Boston, and Pennsylvania. Hotspots are definitely reliable in North Georgia, western South Carolina and North Carolina, and East Tennessee.
They’re invasive species because … Well, they’re not native to this continent, and they’re showing the best sales of native species. This is the fifth year of our “spider” research, as we call them.
And, when you have a lot of people in Joro Spider, you don’t have much other than traditional or weaving spiders of that kind. It is too early to know what their true impact will be, but we are trying to track that.
Gizmo: Why do people look at Joro’s bugs?
Coyle: They are amazingly vain, because they are very comfortable being in the middle of people and places of the world. They won’t come inside the house, but they will be in your backyard, carport, deck, and backyard. They are very big and yellow, so people see them, and we get a lot of calls about these things every fall.
Gizmo: What kind of calls?
Coyle: Broadly speaking, “How do I remove them?” Whether that’s “in the tree I like outside” or “they put a web across the pillars in my house.” The second most common question is, “Are they dangerous? Will they bite me? Will they bite my children? Will they bite my pets?”
Because these webs are huge – they can be 10, 15, or 20 meters across – and you get into them to find a big spider on your head. When old women, these big old ladies with a big yellow color and color, show up all over the place, people think, “holy crap, what’s going on over there?”
Gizmo: And what advice do you give to callers?
Coyle: Actually, this was the reason why we did new studies. We wanted to get concrete answers that weren’t just anecdotal. Based on our team’s combined years of experience, we know what happened here. We needed to do it scientifically to prove it.
Gizmo: I see. And how did you answer these questions on paper?
Coyle: I will start with what we call Management research, that journal of economic Entomology. That answered the question, “How can I get rid of myself?” So we looked online because we thought that’s where people go to find solutions.
We knew there were legitimate spider control products, so we tested several of those. After that we checked with the things we just found on the internet: Bleach, Fulling Trubting, hairdos, and some of these non-troublesome products that people have worked on.
In a scientifically valid and systematic way, we tested each of these compounds on a population of spiders to see if they would kill them, and if so, how long it would take. If not, can we at least make the spider go away? Because for some people, maybe they just want it on their paper – not dead.
What we have concluded is that most commercial products work well. I can’t list any specific products, but if it’s labeled as Spider Control, that stuff works darn well.
Other things worked, too. I mean, mechanical lubrication works, but we don’t condone spraying that all over your yard. It was not what it should have been. We highly recommend using materials written by that purpose, because they work well.
Gizmo: The second paper is about Joro being dangerous, right?
Coyle: On the right. We did a series of experiments where we looked at the spider’s reaction to, basically, a human hand. We went up to the door on the Webs. We have done everything from just holding our hand close to it, trying to touch it, holding it in our hands, stretching it inside, giving it a little.
And in almost all cases, the spider wants to separate. They don’t want to be caught. They don’t want to be touched. If you pay in your hands, they just sit there and freeze. The only time you can really get it to bite is when you press into it, it really grows.
Then we said, “Okay, let’s say someone is exclaiming. How bad is it?” We got 22 volunteers and got them bitten by Joro. We then tracked the itch during the week and had volunteers rate the level of pain based on a system used by pediatricians.
What we found out was that it was like a mosquito bite. So it will be a little swollen, red, and itchy for about 24 hours, so that’s great. And most of the pain levels were very low, like 1 to 2 out of 10.
So the take home message is, if you are going to find a joro spider, you are very venetive to achieve a real spider.
Gizmo: He probably brought it to you.
Coyle: You 100% it brings you. Like, they want no part of you. They would rather not be with you. They would prefer not to be driven by you. They just want to do their thing and be left alone.
And if you bump into them, what’s their response? They will go down to the ground and try to get away from you and turn it off.
Gizmo: Having said all that, do you have any personal advice for getting along with joro spiders?
Coyle: You don’t have to use chemicals to remove these things. The broom works well, your foot works well, and the stick works well. And if you take them out of their web for a few days in a row, they’ll go somewhere else. I always tell people that using chemicals for something like this is often overkill, literally.
After that, another thing is that I will make sure that they will not come to your house. They don’t want to be in your house. This type of spider usually places its webs between large objects outside so things can’t fly into it. So, if there is a joro spider in your house, that means someone brought it there. Plain and simple.
