Joro Spiders in the Garden: Worth the Big Hype?

An unwelcome visitor with monstrous proportions has made its way from Asia to the U.S. Northeast, and we’re not talking about Godzilla.

Instead, all eyes are on the huge, flying Joro spider, which recently popped up in New York and New Jersey, and threatens a full-blown tri-state invasion, according to media reports.

A native of China, Korea, Taiwan, and Japan, the Joro spider (Trichonephila clavate) probably arrived in the U.S. a decade ago courtesy of international container ships.

They took up residence mainly in Georgia, traveled throughout the southeast and have also been spotted in Oklahoma and Maryland. This is the first time they’ve been seen this far north, however, and scientists say they could easily spread thanks to their ability to withstand the cold better than some other spiders. 

Which means a whole new population gets to see these giant arachnids in action.

She’s got legs

Joro spiders are members of the golden silk-orb weavers family, spiders known for their large size, and boy, do they do their kin proud. Some are as big as a human palm (although, incredibly, some other golden silk-orb weaver spiders are even larger than that) 

Female Joro spiders are the larger sex and can reach a body size (cephalothorax and abdomen) of around 0.66 to 0.98 inches; males are smaller with a body size around 0.27 to 0.39 inches.

What’s more impressive, though, is the females’ leg span. At 3 to 4 inches, their spiny legs can be several times larger than their body, giving them the appearance of being bigger overall. When their legs are stretched out, Joro spiders can be 6 to 8 inches long. As if their imposing stature isn’t enough to put arachnophobes and others on high alert, long-legged Joro females are also flashy, with yellow and black coloring. (The shorter males also need to play catch up in the design department, having mostly light and dark brown stripes.)

Of course, when you’re a supersized spider, your web is likely to be, too.

Joro spider webs are circular or orb-shaped golden spectacles that can reach from 6 to 10 feet in diameter. Impressive enough but consider this: they’re also triple-layered. Two irregular layers, one in front of the central orb and one behind it, add stability and may also aid in prey capture. 

Don’t fear the fangs

It’s not just the Joro spider’s appearance that puts people on edge, though. 

They’re also venomous and have fangs. Given those attributes, it’s a good thing Joro spiders aren’t as threatening as they appear to be. In fact, they’re not aggressive at all, preferring to flee rather than fight. The most likely scenario for a Joro spider bite is if it feels threatened or cornered, like if you accidentally grabbed one while gardening. 

And even if they felt like sinking their fangs into you, they might not be able to. Though not exactly ornamental, their fangs are small and may not be able to pierce the skin in the first place. If they do break the skin, their venom is weak and unlikely to cause serious harm, though it might leave a red spot or, in worst case scenarios, trigger an allergic reaction.

Land over there, please

Before you start to ask what the fuss is — they’re just big, gaudy, harmless creatures — there’s one more thing to know: like other young orb-weaver spiderlings, they disperse themselves by “ballooning,” meaning they can float along for miles and land anywhere on unsuspecting passersby. 

Here’s how it works.

Newly hatched spiderlings have special glands that allow them to produce large amounts of silk. They climb to a high point on their mother’s web or nearby vegetation then emit a stream of silk into the air. Because the silk is fine and lightweight, it can catch on air currents, carrying the spiderling away by the breeze. The ballooning silk is like a parachute that allows the spiderling to go long distances. When conditions change, the silk thread loses its lift and the spiderling gently descends — onto the ground and not your hair, we hope. 

Supersize Pest Control 

Despite the media frenzy about Joro spiders taking over the East Coast, they generally do more good than harm, especially by controlling populations of flies, mosquitoes, and other garden pests. When your web is as big as a satellite dish, you’ve got a pretty good trap for a variety of insects.

Because Joro spiders prefer sunny areas with some protection from the elements, you may find their webs near your house, shed, or in trees or shrubs. If their web is in an inconvenient location (for you, that is), you can try to carefully remove it. Just don’t harm the spider in the process. 

While you might not be ready to put out a welcome mat for the Joro spider, it’s good to know that they come in peace. Unlike Godzilla, they’re not here to inflict terrible damage. All the hype is just that. 

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