In 2006, Jumping worms (Amynthas spp.) were first discovered in Loring Park. Since then, they have moved through central and southern Minnesota landscapes at an alarming rate. One reason for this is that jumping worms reach sexual maturity very fast, allowing them to reproduce at a higher rate than other worm species. 

They also process nutrients in the soil faster than traditional earthworms, creating the type of soil that resembles coffee grounds for which they are well-known. This loose soil easily washes away, which increases erosion potential. Also, certain native plant species find it difficult to establish in the churned up soil. Because of this, sites with jumping worms are commonly dominated by invasive plant species, as they seem to be well-suited to establish in this atypical soil type.

Identification  

Jumping worms (Amynthas species) have many characteristics that help in their identification. As the name suggests, when handled, these worms tend to “jump” or violently thrash in an attempt to escape in a way that appears more snake-like than worm-like. They also have the ability to shed their tails, a trait commonly found in many lizard species.

These worms are also distinguishable by the fact that they are almost always found in leaf litter or in the first couple of inches of soil. As they move through the landscape, they process nutrients in a way that creates flakey, light topsoil that is similar in texture to coffee grounds, which is another strong indicator of their presence. Because they reside close to the soil surface, the jumping worm has more pigmentation and a darker appearance than other worm species found in Minnesota.

The most effective way to identify worms in the Amynthas genus is to inspect their clitellum, a ring-like reproductive organ. Compared to other worm species, the clitellum of jumping worms wraps completely around the body and is thinner, closer to the head, less swollen, and lighter in color. 

Lastly, it is important to note that though a commonly held belief is that jumping worms are smaller than common earthworms, this is not the case. The multiple Amynthas species that are present in Minnesota vary greatly in size, and they can be both larger and smaller than what we typically see in our backyards. 

Preventing the Spread

Unfortunately, there is no research-based method for removing jumping worms once they have infiltrated a site. So for now, taking the proper steps to prevent their spread is the only way in which we can reduce the spread of this invasive species. 

The most common way that we have seen jumping worms spread is through transportation of improperly heated compost. When in need of compost, we at Natural Shore work with companies that heat their compost to a minimum of 131°F and turn their piles on a regular basis. This will kill both adult jumping worms and their eggs.  

For our fishing enthusiasts, we recommend avoiding purchasing any type of worms that are labeled something that you don’t recognize, especially if they are advertised as “snake worms”, “Alabama jumpers” or “crazy worms.” And, even when purchasing angle worms or nightcrawlers, make sure to properly dispose of any soil or extra worms in the garbage.

Here are a few more tips to consider. Always use caution when transporting any type of soil. Be careful when accepting plants as gifts, as invasive worms may be tagging along. And never never introduce worms into your soil.  

New Research

On a positive note, researchers are beginning to take a critical look at this invasive worm species in Minnesota. They are addressing questions, like: How do jumping worms spread in Minnesota? Does temperature limit their spread? Is commercial treatment effective? What are the current best management practices? Check out this recent U of MN study to learn more: Jumping worms in Minnesota. 

As new information becomes available, it will undoubtedly strengthen how we all deal with this invasive species. We believe that it is important for individuals, organizations and companies to be aware of the risks and take actions to prevent their spread. With timely education, prevention, and management, we can all work to reduce the environmental impacts from the pesky jumping worms.