Jumping Worm

I was kneeling on our concrete patio when I saw this worm crawling toward me.  It was 10 inches long and moved straight ahead.  It didn't look like any worm I had ever seen and crawling across bare concrete on a warm day was surprising.  It was even more surprising when I tried to pick it up and it went crazy, twitching and flipping around as you can see in this video.

This is a jumping worm, JW, (Amynthas spp.), also called a wiggler, wood eel, crazy snake-worm, Jersey wriggler or Alabama jumper.  This is an invasive species which originated in Japan and Korea, arriving in either horticultural material or as fish bait.  It is now found across Northeastern US and even into Canada.

My JW above stood out because of its length, but identifying them for certain is a little more difficult.  The Minnesota DNR website lists the features quoted below to help differentiate them from our "good" worms such as a European nightcrawler, (Lumbricus terrestris).

• Look for soil with a similar appearance to coffee grounds. As jumping worms eat and excrete waste, the soil gets a unique texture like coffee grounds.
• Jumping worms are very active, move like snakes and secrete yellow mucus when agitated (see video from Wisconsin DNR (link is external) showing their movement).
• When a jumping worm is disturbed, its tail can break off and continue to flail.
• The ring (clitellum) on adults is closer to the end than on nightcrawlers, milky pink to milky gray in color, encircles the whole body evenly, and is barely raised above the skin.
• Setae (tiny hairs the worm uses to move) are evenly spaced around the entirety of each segment, not in pairs or concentrated on the bottom or sides of the body.

Most earthworms in the Northeast are imports.  The receding glaciers 10,000 years ago had wiped out any species that might have existed in the distant past.  In their absence, forests evolved to rely on bacteria and fungi to break down leaves and twigs that litter the floor.  The layers of leaf litter form an ecosystem of their own.  Their loss robs Northern forests of rooting soil as well and increasing erosion.  According to Audubon, it even threatens some species of ground nesting birds that require the litter.

European earthworms arrived hundreds of years ago, likely in ship ballast.  They burrow deeper in the soil, mixing the debris and aerating the soil.  JW specializes in the top soil and can eliminate up to 95% of leaf litter.  This also explains why it was crawling across the open concrete rather than burrowing into the mulch of our flower beds.

The spread of JW has been rapid.  "Where most European worm species move about 30 feet per year, jumping worms can easily cover 17 acres, or roughly the size of 13 football fields, of new ground in a single season."*  Another reason for their success is their parthenogenic reproduction, creating cocoons without mating.  If that isn't bad enough, you can buy 1,000 on line for $72 for gardening or bait!

Northern states like Wisconsin are working on control measures.  Whether they will be as big a problem here in our oak hickory forests remains to be seen.
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