Invasive Asian Crazy Worms Have Been Spotted in More Than a Dozen Places in Maine Over the Past Year

Invasive Asian "crazy" worms (Amynthas agrestis) are increasingly being reported across Maine, according to the state's horticulturist.

Native to East Asian countries such as South Korea and Japan, the worms can now be found in the United States across an area stretching from Maine to South Carolina and west to Wisconsin, according to Maine's Department of Agriculture, Conservation and Forestry (DACF.)

"I would not say we necessarily have a good handle of exactly how widespread they are in Maine, but I do know 13 new locations were reported over the past year," state horticulturist Gary Fish told Bangor Daily News.

Individual specimens of the worms—which are also known as "snake worms" and "Alabama jumping worms"—were actually first spotted in a Maine greenhouse in the late 1890s, however, an established population was not discovered in the state until 2012. Since then several more sightings have been made.

"We believe that crazy worms are not yet widespread in Maine, but they have been discovered in some new locations since 2014, including nursery settings," the DACF said.

"We have been receiving more calls about them in the last 4 years but that may only be due to the publicity," Fish told Newsweek.

In fact, Fish told the Daily News that he had received a call from a resident of Patten—a small town in the east of the state—who said crazy worms had been living on his land for about five years. The worms may have arrived in a load of manure which the resident ordered.

"Now that manure is spread all over his property and the worms are proliferating and he's concerned they are crazy worms," Fish said.

While Fish was not able to confirm with 100 percent accuracy that the specimens were indeed Asian crazy worms from the photos the Patten resident sent him, the horticulturist said he was fairly certain that they do belong to the species.

"Crazy worms are 'Asian' worms that are much like the 'European' earthworms that we have all known for years," Fish told Newsweek. "They are different in a couple ways. They feed voraciously on the leaves, mulch and organic matter at the soil surface in the forest or in landscape beds. They writhe and dance like a snake so many people also call them 'snake worms' or 'Alabama jumpers.'"

"They have a very distinct smooth, milky-white clitellum which is a reproductive organ in worms," he said. "They are the same size as the worms you might see on the sidewalk after a hard rain. They are also able to reproduce on their own so only one worm or overwintering cocoon can start a new population."

Invasive Asian crazy worms pose an ecological problem because they can alter the composition of the soil by speeding up the decomposition of fallen leaves which cover the ground.

earthworm
Stock photo: An earthworm moving through soil. iStock

"They turn good soil into grainy, dry worm castings—or poop—that cannot support the native understory plants of our forests," the DACF said. "Other native plants, fungi, invertebrates, and vertebrates may decline because the forest and its soils can no longer support them.

"As native species decline, invasive plants may take their place and further exacerbate the loss of species diversity. If allowed to spread, crazy worms could cause serious damage to horticultural crops and the forest ecosystem in Maine," the department said.

Because they destroy the leaf litter so quickly, the trees end up with exposed root systems which causes moisture stress—or drought damage—and a greater potential for root infections, according to Fish.

"They also remove a very important seed bed for spring ephemeral flowering plants which are very important for many insects, birds, amphibians, reptiles and small mammals," he told Newsweek. "Loss of the lower levels of the food web cause ripples throughout the food chain. A couple of animals that could be disrupted are wood thrushes and the red-backed salamander. Both need the moist leaf litter under the forest trees to nest or overwinter [respectively.]"

When they are threatened, these worms jump and thrash about, explaining why they have gained the "crazy" moniker.

This article was updated to include additional comments from Gary Fish.

Invasive Asian Crazy Worms Have Been Spotted in More Than a Dozen Places in Maine Over the Past Year | Tech & Science