Some people call it a crazy worm. Some call it an Alabama jumper, although it’s not contained to that state.
It’s Amynthas agrestis, one of three main species of earthworm native to southeast Asia that have found their way to North America.
It can be distinguished from other earthworms by a thick tan-gray band around part of its body, which can range from 1.5 inches to 8 inches.
But it’s even more distinguishable by what happens when you touch it. Unlike other earthworms, which might recoil or slowly crawl away, the invasive Asian jumping worm lives up to its name by aggressively flailing as it tries to escape.
The Asian jumping worm is well established along the eastern U.S., including Pennsylvania, and has been reported in more than 40 states.
It is aggressive in its eating habits and life cycle, according to Penn State assistant research professor and entomologist Michael Skvarla.
“The earthworms we already had in North America lay about 50 to 100 eggs over a five- to 10-year lifespan. They have a fairly slow life cycle,” Skvarla said. “Jumping worms compress all of that into about five months. They hatch, eat, lay their eggs and die with the onset of cold weather. And then new worms hatch in the spring.”
In order to fuel that fast life cycle, jumping worms must consume much more food than their counterparts.
“They burn through leaf litter to try and get enough nutrients for this ‘live fast, lay eggs, die fast’ lifestyle,” Skvarla said.
And unlike other earthworms — whose castings are released underground to leach nutrients into the soil and promote plant growth — jumping worms live in the top inch of soil and spend much of their time above-ground in leaf litter.
As a result, their castings remain on top of the ground, where they dry out instead of breaking down.
“That makes them bad for forests,” Skvarla said. “It affects nutrient cycling and carbon cycling. If the nutrients the plants need are sitting on top of the soil as dry jumping-worm poop, that’s going to affect their growth.”
While the Asian jumping worm is a significant concern, it’s only the most recent wave of earthworm invasions to alter the American landscape.
“What we think of as the common earthworm is an invasive species that came over on boats from Europe,” Skvarla said. “Pennsylvania lost its few native earthworm species when the entire state was logged in the late 19th and early 20th centuries.
“European earthworms moved in, and they’re not as bad as the jumping worms, but they still naturally degrade leaf litter. And that’s not how our forests historically processed fallen leaves.”
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“Twenty years later, they started being documented in Maryland and New York,” he said. “Most invasives around for 15 to 20 years before their populations reach a level where people begin to notice them.”
The good news? They can be controlled, at least on a small scale.
“We had them in our garden when we moved into our house,” Skvarla said. “But because they live so close to the surface, they don’t do well in turf. We let our garden go for a couple years until it turfed back over, the worms died, and we could plow it and use it again.”
Below, YouTube gardener Growing Wisdom shows what the worms look like and do.
That approach can’t be replicated over acres of forest, however, which means the Asian jumping worm is here to stay.
Skvarla said he hopes that will encourage a state or federal agency to learn more about it.
“Worms kind of fall through the cracks,” he said. “I’m an entomologist, which biologically doesn’t include worms. The state Agriculture Department doesn’t deal with them because they’re not listed as an agricultural pest.”
With an invasive such as the spotted lanternfly, which was threatening Pennsylvania grape vineyards, state agencies collaborated, funded research and looked at ways to address the problem.
“That doesn’t really happen with worms,” Skvarla said. “There hasn’t been any real state or federal push to address it.”