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The "Asian jumping worm," or Amynthas agresitis, is an exotic species of worm recently found in Oregon that has already caused extensive ecological harm on the East Coast.

(Oregon Department of Agriculture)

An exotic species of earthworm, sometimes called "Asian jumping worms" or "Jersey wigglers," have turned up in multiple Oregon locations, officials confirmed Thursday, and the discovery could spell bad news for forests in the Pacific Northwest.

Jim Labonte, senior taxonomic entomologist at the Oregon Department of Agriculture, said the worms are distinctive for their behavior, which sets them apart from other more sedentary annelids.

"They don't look very different, other than they are a little more slender," he said. "But these worms can thrash about so violently when they are disturbed that they can get clear off the ground."

The critters, also sometimes referred to as "crazy snake worms," also have tiny raised ridges between each of their segments, Labonte noted, though they are hard to detect with just the naked eye.

Officials have gotten reports of the worms from eastern Oregon in the past, but the two discoveries of the wigglers this year -- one in Grants Pass and another in Clackamas County -- mark a significant proliferation of the species.

The worms reproduce asexually -- no mate needed -- so it doesn't take a significant number of them to establish a new population, Labonte said.

Scientifically known as Amynthas agrestis, the worms have been on the East Coast for years, Labonte said, and the risk they pose is in their diet.

As opposed to Oregon's native earthworms, which feed deep in the soil, the new exotic worms feed on the shallow layer of detritus that rests on the forest floor. That layer is crucial to water retention and for forests to regenerate as it provides a bed of nutrients in which seeds germinate.

"Exotics work on the surface and that top layer is really important for forest health," Labonte said, noting that the impact the worms will have in Oregon is yet to be determined. "We don't know what they'll do out here, but in the east they have caused quite a bit of ecological harm."

Beyond their feeding habits, Labonte said the species could potentially crowd out Oregon's native earthworms as they compete for resources.

It was unclear exactly how the worms got to the west, though Labonte said they could have hitched a ride on potted plants from Asia, been distributed by fishermen disposing of bait or passed through the hands of composters who often trade worms.

With their potential impact still unknown, the Department of Agiculture is still weighing its options on how to combat the worms. Labonte said nearly 100 exotic species have been discovered in the state since 1997 and, with limited resources, his agency has to pick and choose which problems to tackle.

Of the 250 worm species found in North America, roughly 60 are considered exotic, Labonte said.

"We've got a lot of exotic fish to fry, as they say," he said. "A lot of them aren't a problem, but some of them can be major pests, like this one."

That's where the public comes in, Labonte said, calling for a bit of "citizen science." He asked anyone who spots a suspicious worm wriggling about to collect the critter, put it in a jar with some dirt and keep it in a cool space until they can contact the Department of Agriculture to turn over the specimen.

He asked the public not to send in dead worms, for obvious reasons.

-- Kale Williams

kwilliams@oregonian.com

503-294-4048