These huge Asian spiders that can fly (sort of) are heading for Canada

The Joro spider can be eight inches long and can ‘balloon’ as a way to travel through the air. But don’t worry — they aren’t dangerous

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A spider from Asia has made its way to North America. It also flies — sort of.

If that wasn’t enough, the Joro spider is an absolute monster — they can be up to eight inches long and, as a bonus, they’re venomous.

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The spiders were first spotted outside of Asia, where they generally reside in Japan, South Korea, China and Taiwan, in 2013, when they were found in the southeastern U.S. state of Georgia.

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“There’s a lot that’s unknown. This is an evolving situation. It seems they’re not threatening, particularly to humans. The potential ecological implications are important, but there are a lot of other major things happening to our ecosystems with climate change and other factors as well,” said Brendon Larson, an expert on invasive species at the University of Waterloo in Ontario. “It’s just important that people not be too sensationalistic about this issue just because they’re spiders.”

The National Post spoke to Larson about the spiders. This interview has been edited and condensed for clarity and length.

How did they get to North America?

They probably came in with something that was being shipped here, like cargo, and they were in the cargo, and then they escaped from that. And that’s how they colonized North America.

Are Joro spiders dangerous?

My understanding is they’re not dangerous to people or pets. Like many spiders, they have a toxin. But that’s used to kill little insects and their jaws can’t even penetrate human skin, is my understanding. So, they’re basically harmless to humans. But, of course, a lot of people are afraid of spiders. So, there’s that kind of effect, even if they’re not actually dangerous.

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What might they do to other spiders or insect species?

The reality is, it’s a little too soon to know what those impacts will be. In Georgia, it does appear that they are replacing some of the other spiders that are there. It’s kind of different, bigger spiders, rather than the spiders that were there.

And I’m speculating here, but one possibility is that they’re bigger so they set up their bigger web. And they’re catching more of the insects that are flying around. Or, maybe if there’s a really good place to put a web, maybe they’re able to build their web there, and not let other spiders because they’re bigger, they can defend that space against other spiders. But I don’t think they’re eating other spiders.

One concern is pollinators, for example. So, it could be bees, it could be flies, it could be butterflies, and these are the insects that get caught in any spiderweb. So, that’s not new, it’s just that these are a different species. And if they have bigger webs, and there’s a lot of them, then they could have an impact on those flying insects.

Is there anything significant about their existence that researchers have found?

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The main thing that’s new here is just that they’ve been introduced to a place where they didn’t exist before. And they’re large. But we already have large spiders in southern Ontario. So there’s nothing particularly different or distinctive about these other than that they’re new for us.

Do Joro spiders fly?

There are media stories about the spider and it talks about them ballooning, which is a way that they can distribute themselves and move from one place to another. And what that is, is they let out silk. And that silk gets caught in the breeze. And then they can be lifted up in the air and carried long distances. And that’s how they can move fairly quickly from one place to another, and how they might very well gradually spread northwards. But that’s not unusual, and lots of spiders do that.

There aren’t going to be these gigantic spiders flying around in the air, because, first of all, they don’t fly, they’re just gliding around. And the other thing is, it’s not the adults, it’s the little baby spiders, which are just tiny. The big spiders, it’s just too big, they don’t do that. So, it’s nothing to be really afraid of. And again, spiders do this. They’re already doing it.

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When do you think we could see Joro spiders in Canada?

They’re not in Canada at this point. They’re in West Virginia right now and they’re in Washington, D.C. So, the reality is we don’t actually know for sure they will get here. There is some recent research that’s been looking at whether they’re likely to arrive in Canada.

We just don’t have enough information. They could show up next summer, but they might not be here for 10 years, they may never be here. The models are saying we should probably prepare for them to be here. But we don’t know that for sure.

If they do arrive, is there anything Canada can do to be prepared for their arrival?

There’s only so much we can do to control a species like this. You can kill an individual spider, you can kill a couple spiders if they’re near your house, but that’s ultimately not going to do very much. So, at this point, I’m not really sure what we can do.

If they do come, we can’t stop them at the border.

I’m not aware of any great solution for controlling them other than very local solutions, like, you see a spider and you spray it or something.

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