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Jumping Worms Have Invaded Wisconsin

A wriggling worm is becoming a problem in the Midwest

Jumping worms are becoming more common in Wisconsin. This photo shows what is likely an Amynthas agrestis jumping worm in Pennsylvania, though its identification is unconfirmed. (Tom Potterfield/Flickr)
smithsonian.com

A new resident has made its home among the cheeseheads, and it is not welcome.  The invasive jumping worm (Amynthas sp.) now inhabits five of Wisconsin’s counties, and the state’s Department of Natural Resources (DNR) is looking to the public for help in stemming its spread, as Breann Schossow reports for Wisconsin Public Radio.

Wisconsin is home to many non-native earthworms, which arrived with the state’s first settlers, but the jumping worm has become a unique case for a few reasons. Originally from East Asia, the worms cause problems in how they digest leaf litter and poop out soil. Most earthworms eat soil, so what’s the big deal with this one? As Bernie Williams, an invasive species specialist with the Wisconsin DNR, told Schossow, jumping worms are total overachievers:

"This particular worm seems to change the soil so it almost just becomes granular. It doesn't hold any moisture any longer, and you do see declines, anecdotally, in some of the plants that are in the surrounding areas where this earthworm has invaded."

Like many successful invasive species, the jumping worm is also really good at making more jumping worms. It grows quickly and munches through soil fast.

Named for their unique wriggling behavior when disturbed, the worms were first discovered in Wisconsin in October 2013. Williams was leading a routine field class at the University of Wisconsin-Madison Arboretum, showing students how to identify insects, when she stumbled upon a jumping worm, as Sheila Eldred reported back in 2014 for Discovery News. That was the first confirmed sighting in the state.

Ecologists had hoped that a winter freeze might kill off the invasive population, but they stuck around. There is some evidence that their cocoons might be susceptible to a controlled burn, as Lee Bergquist writes for the Milwaukee Journal Sentinel. DNR officials told Bergquist that the worm could be in up to 14 counties, though it’s only been confirmed in five.

Though the worms are only just making their way to the Midwest, some jumping worm species came to North America as early as the 1800s. They’ve since caused problems in other areas of the U.S. as well — notably some Northeastern States and the Great Smoky Mountains. Bergquist explains, the worms likely hitch a ride from state to state in transported soil.

About Helen Thompson
Helen Thompson

Helen Thompson writes about science and culture for Smithsonian. She's previously written for NPR, National Geographic News, Nature and others.

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