These 'Crazy Worms' Are Poised To Wreak Havoc On The Midwest


wisconsin arboretum asian crazy worm

UW Arboretum

The Asian "crazy worm" looks pretty harmless, as earthworms do, but the little worm can do big damage.


Unlike the vast majority of approximately 5,00o earthworm species on the planet, Amynthas agrestis, also known as the Asian crazy worm or Alabama jumper, is actually considered a destructive invasive pest, and it has scientists seriously worried.

The worms showed up in Wisconsin for the first time in the fall of 2013, at the arboretum of the University of Wisconsin-Madison. But now it has done something scientists were hoping it wouldn't - it turned up again, proving that it can survive the Wisconsin winter (and if you recall, this past one wasn't just any winter).

"We knew their introduction into our state poses a huge threat to the future of our forests," said Bernie Williams, an invasive species specialist in forest health at the Wisconsin Department of Natural Resources, in a press release from the University of Wisconsin.

The worms are originally found in Japan and the Korean peninsula. They grow to 8 inches long and are marked by a light band around their dark bodies - and as you can see in the gif below, they really do jump around like crazy.


In 2009, Scientific American reported that the wriggling invasive pest (along with its kin, the night crawler) was clearing forest floors around the Great Lakes, devouring the layers of the forest floor that new trees depend on to grow, turning a "lush understory" into a barren area with "virtually no tree seedlings."

Wisconsin hasn't had native earthworms for 20,000 years - they were wiped out by the last glacier to cover the state. And while most species currently there don't cause problems and actually aerate soil for gardeners, these ones are trouble, with voracious appetites and an incredibly rapid breeding cycle.

"It breeds en masse, and is constantly dropping cocoons," Williams said in the news release. "Where the cocoons hatch, at the soil surface you'll see what looks like small filament hairs moving on the soil surface in large numbers."

These worms have been in the southeastern United States for decades, but their spread to new ecosystems that are healthy in their absence is a disturbing development.

Researchers aren't sure how the worms ended up in Wisconsin. Theories include fishermen tossing leftover bait, worms trapped in tire treads, and mulch that is brought into the area.


By clearing the forest floor of normal plants and leaf detritus, the worms encourage erosion and make it easier for other invasive species to gain a root-hold. It also eradicates the natural habitat for local flora and fauna.

They don't generally spread quickly without being carried somewhere, but are considered essentially impossible to eliminate when they get there.

Here's the full video that gif is from: