Expert issues warning as unusual spiders spread into new US territory: 'An invader'

A striking spider is rapidly taking over Maryland's wilderness, according to WMAR. 

What's happening?

The Joro spider is a vibrant black-and-yellow arachnid native to eastern Asia. It initially appeared in Georgia in 2022 and has since been seen appearing in small pockets throughout the U.S. The latest sightings in Elkridge, Maryland, have caused concern among experts. 

"This is kind of like the very first example that's showing up that you know the species is exhibiting all these like classic characteristics of an invader where it moves in; it grows rapidly in population like very, very quickly," said local biologist Angela Chuang, per WMAR.

Why are Joro spiders important?

Invasive species can be highly damaging in unforeseen ways. When an animal or plant is taken from its native habitat, it's also freed of the predators that kept its population in check. In a new environment, this can lead to unfettered growth, a monopoly on vital resources, and the pushing out of native species. 

This can lead to a decline in ecosystem services. One study suggested that over the course of 50 years, invasive species have incurred costs of over $1 trillion.  

What's being done about Joro spiders?

Luckily, the Joro spider hasn't had a massive ecosystem impact yet. Their bites aren't especially harmful to people. Some researchers even suggest its presence could be a boon, as the Joro spider feeds on pesky mosquitoes, flies, and stink bugs. 

Stink bugs are wildly invasive and destructive. Mosquito populations have been rising due to wetter, warmer weather, increasing their ability to spread disease. Any natural combatants to these pressures are welcome.  

That said, Chuang said it's entirely up to locals whether they stomp Joro spiders on sight. The Joro spider was originally spotted in the U.S. thanks to the citizen science app iNaturalist. Keeping an eye peeled for unusual critters and sharing data on such platforms can help inform researchers and build robust management plans.

What's the hardest thing about taking care of your yard? Mowing the lawn 🏡 Controlling weeds 🌿 Keeping pests at bay 🐿️ I don't have a yard 🤷 Click your choice to see results and speak your mind.

Get TCD's free newsletters for easy tips to save more, waste less, and make smarter choices — and earn up to $5,000 toward clean upgrades in TCD's exclusive Rewards Club.