Watch out for jumping worms Story by Larry Hodgson, Photo by Josef Görres.
Amynthas agrestis worms on a mulched bed.
A
siatic jumping worms (Amynthas agrestis, A. tokioensis and Metaphire hilgendorfi), also called snake worms or crazy worms, seem to have been introduced accidentally into the southeast United States in the 19th century, probably through contaminated nursery stock imported from Japan or Korea. But they’re spread into the North seems recent, within the last 15 years. They’re already present in all Northeastern US states and lately seemed to have pushed across the Midwest showing up here and there and now across the Rockies into Oregon and to have jumped the border into Ontario, although their presence is still very sporadic throughout this vast territory. What are they? Jumping worms are large, plump earthworms, up to 8 inches in length, looking much like the common earthworm (Lombricus terrestris), also called nightcrawler or dew worm, but with a startling habit: they jump and thrash when disturbed! They’re very animated and tend to remain on the soil surface. Their subsequent movements are snakelike rather than wormlike, as they slither from side to side. As for why they’re called crazy worms, well, I think any earthworm that jumps when you bother
38 • 2021
Scan me
Check out Larry Hodgson’s internet blog The Laidback Gardener here! https://laidbackgardener.blog/
it is likely just a bit crazy, don’t you? They’re not just present in northeastern North America. They’ve become established many other parts of the world. In the southeastern US, where they’ve been around for more than a century, they may be called Alabama jumpers or Georgia jumpers. In Europe, when they are also now present and spreading rapidly, a different series of Amynthas species seems involved. How to recognize Them If jumping and thrashing isn’t enough warming that these are not your average earthworms, look at the clitellum, the “ring” earthworms have around their body. That of the jumping worm will be smooth and light-colored, sometimes almost white, not the same color as the rest of its skin as that of the nightcrawler, and almost flush with the skin rather than bulging and ridged. They’re dark Issue 1
worms, almost gray in color, with a glossy smooth skin. They will occasionally lose their tails as a defense mechanism to escape predators. Jumping worms don’t dig tunnels, nor do they feed underground, but remain near the top of the soil, in the top few centimeters, feeding on leaf litter. Instead of leaving their excrement in little piles of castings as is typical of nightcrawlers, they cover the soil surface with dry, grainy, pellet-like castings that look somewhat like dry coffee grounds, keeping seeds from sprouting and destabilizing soils. They are best recognized in late August and September when they have reached their full size. Life cycle Unlike nightcrawlers, which can live six years or longer, jumping worms have an annual life cycle. The adults die in late fall, but leave tiny cocoons, difficult to spot, that overwinter. They have been known to survive temperatures as cold as -40 Fahrenheit. They grow quickly in the spring, outcompeting and often eliminating other earthworms. Hermaphroditic, they can reproduce sexually, but also parthenogenetically, producing cocoons without fecundation, so it takes only one to start a new colony. There are two generations per localgardener.net
