'Crazy worms' bombard forests of 15 US states

They look like normal earthworms, but they can writhe, jump, and even shed their tails to escape danger.

Some people call them "crazy worms," ​​and now scientists are finding them spreading to at least 15 states across the United States.

Josef Görres, a soil scientist at the University of Vermont, described the "madworm" problem as "an invasion" that is dangerous to animals and plants, and especially to sugar maple trees in the northeastern United States.

It is an invasive species that first arrived in North America in the 19th century, loaded onto ships carrying plants.

"People often think of earthworms as beneficial. But in the forests of northern America, they have the potential to have a huge impact ," Josef stressed.

Worms of the genus Amynthas — also known as snake worms, Asian jumping worms, and Alabama worms — love to break down the rich, nutrient-rich layers of decaying leaves that cover the forest floor, which can be very damaging to forests, including sugar maples. They're an invasive species that first arrived in North America in the 19th century, loaded onto ships carrying plants. Since then, they've spread like wildfire and have now been seen in more than a dozen states, including Minnesota, Wisconsin, Missouri, Illinois, Iowa, Nebraska, Ohio, Texas, Louisiana, Indiana, Kansas, Indiana, Kentucky, Tennessee, and Oklahoma.

Where did the name "mad worm" come from?

"They are actually extremely active worms that like to jump, wiggle and squirm constantly. That's where the name 'crazy worms' comes from ," Mr. Görres shared, adding that crazy worms can even launch themselves into the air thanks to their violent wriggling.

In addition, crazy worms also have the ability to cut off their own tails like salamanders to defend themselves. Once crazy worms have cut off their own tails, they cannot regenerate a new tail. This is like a "crazy worm " escape route that can only be used once .

"When you see that moment, it's pretty crazy. It's a one-time defense mechanism to fool a predator like a bird. When it senses danger, the crazy worm will cut off its tail. The tail keeps wagging as if to say, 'I'm a worm, grab me,'" Görres describes.

A 'crazy worm' was discovered in Wisconsin.

They resemble regular earthworms, only smaller and brownish in color, but they are destructive to soil. According to Smithsonian, adult crazy worms reproduce rapidly and without a mate, laying clutches of dirt-colored eggs. When they hatch, they quickly eat the nutrients in the topsoil around them, leaving behind a grainy mess that resembles coffee grounds.

Scientists believe that these earthworms not only change soil structure and nutrient dynamics in the soil, but also replace other earthworm species there.

Asian jumping worms feed on this layer of leaves, causing soil moisture to change and seeds to fail to germinate, especially in maples, oaks, red oaks and birches. The CDFA warns that these voracious worms can devour thick layers of organic matter in two to five years.

It's unclear how these worms continue to spread across the U.S. According to a January 2020 article in The Atlantic, scientists believe the worms may have spread from state borders to importing plants by clinging to the treads of truck tires or even by boat, where they can travel surprisingly far underwater.

Researchers are still investigating the long-term impact of the worms on North American forests, but in the short term, it is clear that they are harmful to soil and native worms. Officials in 15 US states have concluded that the madworm invasion is a major threat to native environments and have raised alarms about its spread.

US experts admit that they have not yet found a specific way to limit the spread of Asian jumping worms nationwide. They have made some recommendations such as pouring a mixture of water and yellow mustard seeds on the soil, or covering moist soil with clear polyethylene sheeting for two to three weeks until the soil temperature exceeds 40°C to destroy the cocoons. Another way is to put the worms in a bag, leave them in the sun for 10 minutes, then throw them away.