Chilmark gardener Susan Straight has opened up quite a can of worms.

She recently gave me the scoop on a group of soil sorcerers whose magic is of the black variety. The worms in question are a type of earthworms called Asian jumping worms and their presence and practices are new to me.

Asian jumping worms, also known as crazy snake worms, are invading American soils. These jumping worms, members of the genus Amynthas and the genus Metaphire, have become established in the region and are even be found on our little Island.

Like most of us, they took the ferry. But you would never see them in a deck chair – jumping worms arrived stealthily and steadily in mulch, compost and in the soils of nursery plants destined for your home or business.

They turn on their head the idea that earthworms are good for soils and plants. Most of us know of the benefits of earthworms but many of us don’t realize that most earthworms in this country are not native, having come from far-away lands.

What makes these Asian varieties harmful is their unique lifestyle and ability to reproduce faster and more efficiently than your garden-variety European earthworms, which they easily outcompete.

Jumping worms have been described as night crawlers on steroids. They live in the leaf litter and the top layer of the soil where they consume the organic layer of soils and the nutrients within the soils rapidly, taking them away from the plants that need them for food and habitat.  

It has been estimated that a large population of jumping worms can reduce leaf litter in a forest by 84% to 95% in just four months. With the surface and upper layer of the soils thus denuded, plants cannot get nutrients and can die. Those plants that can survive are often eaten by deer that now have access in a less-dense woodland. 

Ground-nesting birds can also decline, as lack of cover provides added access to their nests for predators. And in a perverse twist, the plants that can thrive in this onslaught are invasive species themselves, including Japanese barberry, common buckthorn and multiflora rose.

To add insult to injury, jumping worm droppings are not soil amendments but rather reduce the quality of the soils. In one study, it was discovered that jumping worms can uptake and store large amounts of lead and mercury and pass them along to the birds and other wildlife that eat these worms. The researchers suggested that these creepy crawlers might be the smoking gun for high concentration of these metals in ground-foraging birds.

Jumping worms have succeeded well in expanding their population and range due to a number of factors. They mature twice as quickly as their European counterparts, reproduce faster, are more aggressive and have higher population densities. There are also very few control methods to prevent their spread. These worms can even breed asexually by parthenogenesis which is the ability to reproduce from a body part.

Trying to capture (or even photograph) these worms is difficult due to their frenzied nature. To escape your grasp, they will separate from their tail (which, as mentioned, can develop into a new worm).

Identify them by their crazy behavior, timing (most likely to be found in August and September when they are biggest) and their clitellum (narrow band around their body) which is smooth and white and completely encircles them. Contrast that description to the raised, three-quarter round pink clitellum of European earthworms.

Find these crazy jumpers to your dismay as there isn’t much you can do once you have an infestation. Prevention is key – check your plants, mulch and soils and be wary about sharing plants with others, a practice that can inadvertently spread this warrior worm. If you have them, leaving them in a bag in the sun will kill them. And remember: forget death by dismemberment since the slicing of these worms will simply make more.

Charles Darwin, contemplating the effect worms have on the planet’s surface, wrote: “it may be doubted whether there are many other animals which have played so important a part in the history of the world, as have these lowly organized creatures.” To which the jumping worms might likely answer, “You haven’t seen anything yet!”

Suzan Bellincampi is director of the Felix Neck Wildlife Sanctuary in Edgartown, and author of Martha’s Vineyard: A Field Guide to Island Nature.