Invasive 'Crazy Worms' Found in Wisconsin

Researchers have found Asian crazy worms in Wisconsin-Madison.

According to researchers at the University of Wisconsin-Madison, the UW Arboretum is the first confirmed site for Amynthas agrestis. These earthworms are native to Japan and South Korea and are an invasive species in the U.S. Experts believe that the earthworms hitched a ride with the landscaping plants that were imported from Japan and Korea.

These hungry earthworms have a large appetite and can eat all the organic matter in the soil in a short period of time. Absence of organic matter makes the soil dry and barren. Researchers said that the worms change the structure of the soil.

Amynthas can be distinguished from other earthworm species by their grayish coloring. These worms can grow to up to eight inches long. Other names for these organisms are crazy worm, snake worm and "Alabama jumper." A. agrestis are also found in Vermont.

"Amynthas was listed as a prohibited species under Invasive Species Rule NR 40 since its adoption in 2009, because we knew their introduction into our state poses a huge threat to the future of our forests," said Bernie Williams, invasive species specialist in forest health at the Wisconsin Department of Natural Resources.

Earthworms are considered as friends of farmers and gardeners as they loosen and aerate the soil. But, not all earthworms are good. Invasive species of these worms have the ability to destroy local biodiversity.

Most earthworms in the Wisconsin were brought by European settlers. Researchers said that the European species can harm the local landscape, but their population seldom reach critical levels.  

These crazy worms can mature in just 60 days, which means that the populations of the worms can double during warm months. Also, these earthworms can reproduce without mating.

"Amynthas' lifecycle is completely different from European species of earthworms," Williams said in a news release. "It breeds en masse, and is constantly dropping cocoons. 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."