Invasive Jumping Worms That Violently Thrash If Handled Now in at Least 15 U.S. States

A highly invasive species of jumping worm first spotted in Wisconsin in 2013 has now been found in more than a dozen Midwestern states.

The worm, Amynthas spp, is native to East Asia but is believed to have been brought into the U.S. as fishing bait. Scientists warn they feed on organic matter in soil, eating many of the crucial nutrients that plants, fungi and animals require to thrive.

When the species was first introduced to the country it was limited to regions along the U.S. coasts, but has since spread inland, KTVI reported.

As of 2021, distribution includes Missouri, Illinois, Wisconsin, Iowa, Kansas, Nebraska, Oklahoma, Texas, Louisiana, Indiana, Minnesota, Indiana, Kentucky, Tennessee and Ohio, the news outlet noted, citing specialists from the University of Illinois that last week confirmed that the invasive worms were discovered in Peoria County.

Jumping worms earned their nickname due to their behavior, with the species known to violently thrash when handled. Scientists have documented that they have snake-like movement and can shed their own tails to escape when put under duress.

They are also known as crazy worms, Alabama jumpers or snake worms, according to Illinois University Agriculture and Natural Resources expert Nicole Flowers-Kimmerle, who noted in a blog the mature worms are between four and five inches long.

"These worms are known... damage plant roots, and alter water-holding capacity of the soil. This is especially a concern in our forests, where organic matter is limited. It is important to stop the spread of jumping worms," she wrote last week.

Due to their appetites for soil nutrients, the worms grow twice as fast as other species. They reproduce without mating and "damage roots severely, causing weaker plants that are more susceptible to pests, drought, and disease," Flowers-Kimmerle explained.

The Wisconsin Department of Natural Resources says in a fact sheet that the jumping worms are brown/gray with a white band called clitellum encircling their body.

Unlike the more common European nightcrawler species of worm which has a thicker and slimy exterior, jumping worms are "sleek, dry, smooth and firm." While adults won't be able to survive through cold Midwestern winters, their egg casings can.

Population control is a problem, and experts have conceded there are no viable control measures in place to reduce the worms from spreading across the country.

Jumping worms are typically found in the top few inches under the ground, and people are urged to keep an eye out for them from the mid-to-late summer period. One key sign they are lurking is that soil takes on the appearance of coffee grounds.

Scientists said these are the most common ways to prevent spread:

  • Remove adult jumping worms. Place adults in a plastic bag and leave in the sun at least 10 minutes. Dispose of the bag in the trash.
  • Do not buy jumping worms for bait, vermicomposting, or gardening.
  • Only purchase compost or organic matter that has been heated to appropriate temperatures and duration to reduce the spread of pathogens, insects, and weeds. Jumping worm egg casings do not survive temperatures over 104 degrees F.

The full list of jumping worm prevention tactics can be found via the websites of the University of Illinois and the Wisconsin Department of Natural Resources.

Flowers-Kimmerle wrote in the blog: "Removing adult jumping worms to decrease the number of egg casings produced is the best control available at this time. Adults placed in plastic bags and left in the sun die quickly. Dispose of the bag in the trash."

Stock: Worm close-up in a fresh wet
Stock: Worm close-up in a fresh wet earth. A highly invasive species of jumping worm (not pictured) first spotted in Wisconsin in 2013 has now been found in more than a dozen midwestern states. iStock