Jumping worm (Amynthas species)

jumping worm in flower bed

Photo by Josef Gorres, University of Vermont.

Description

Appearance

Jumping worms are a type of earthworm. They are called “jumping worms” because of their unusual behavior when disturbed – they move like a snake and sometimes appear to be jumping. A light-colored ring extends around the body and is closer to the head than in other earthworms.

 

Biology

Jumping worms refers to multiple species, all in the genus Amynthas. Jumping worms live and feed in the leaf litter layer on the soil surface and in the top few inches of the soil, but do not create burrows. They produce cocoons in late summer and early autumn. Then the adults die and the cocoon stage survives through the winter. Cocoons hatch in early spring and adults mature in summer. Amynthas are able to survive a variety of conditions including cold winter temperatures.

Origin and spread

No earthworms are native to Minnesota and other northern states. Jumping worms are native to Asia. People spread jumping worms throughout North America by moving potted plants, soil, compost, mulch and fishing bait.

Researchers at the University of Minnesota have confirmed jumping worms in Minnesota. Dr. Lee Frelich first observed Amynthas agrestis in Loring Park in Minneapolis in 2006. Dr. Frelich has also observed jumping worms on the University of Minnesota St. Paul campus since 2007.

Means of spread include:

  • Moving soil, potted landscape plants, sod, mulch (including bark mulch or woodchips), or compost can move earthworms and their cocoons from one place to another.
  • Earthworms, such as red wigglers (Eisenis fetida) purchased for composting may be contaminated with jumping worms.
  • Earthworms purchased for fishing bait, such as European nightcrawlers (Lumbricus terrestris) may be contaminated with jumping worms.

Don't be fooled by these look-alikes

Keys to jumping worm identification include:

  • 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 showing their movement).
  • When a jumping worm is disturbed, its tail can break off and continue to flail.
  • The ring (clitellum) on adults is 14-15 segments from the head which is closer than on nightcrawler species which have a clitellum 23-32 segments from the head.
  • The clitellum is 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.

Jumping worms can look similar to European nightcrawlers (Lumbricus terrestris).

View the “Meet the Jumping Worm” (University of Minnesota) webpage for detailed identification information and comparisons to other worm species.

Regulatory classification

Beginning July 1, 2024, jumping worms (Amynthas and Metaphire species) were listed as prohibited invasive species in Minnesota. It is a misdemeanor to possess, import, purchase, transport or introduce jumping worms without a permit.

Threat to Minnesota

Invasive species populations may cause recreational, economic and ecological damage and can change how residents and visitors use and enjoy Minnesota lands and waters.

Jumping worm impacts:

  • Jumping worms can dramatically change soils, giving it a unique texture similar to coffee grounds. Jumping worms feast on mulch and strip vital nutrients from topsoil. This kills plants and increases erosion. Homeowners may see garden plants killed and may have difficulty growing plants.
  • Jumping worms can cause environmental harm where they are established. Studies have found nonnative earthworms dramatically change forest soils by eating the leaf litter layer and impacting soil chemistry, soil organisms and plant communities. Jumping worms have been shown to have similar effects. When the soil changes, the forest can’t support the same plant and animal species it did before earthworms.

What you should do

You can help prevent the spread of jumping worms.

  • Everyone:
  • Anglers:
    • Dispose of unwanted bait worms in the trash. Never release any worm into the environment – all earthworms are non-native to Minnesota.
    • The common bait worms in Minnesota are different species than jumping worms, but are still harmful to forests. Continue to dispose of unused bait worms in the trash.
    • View the video Jumping worms: What anglers should know.
  • Gardeners:
    • Be on the lookout for jumping worms in soil, potted landscape plants, mulch or compost. You might see soil that looks like coffee grounds or notice unusually jumpy worms in your mulch. Don’t move any material that might be harboring jumping worms, and report any suspected jumping worms to the DNR.
      • Look for a compost supplier that follows the “process for further reducing pathogens” in their composting method. This process makes sure that compost reaches high temperatures (131°F or above) and involves turning compost piles on a schedule. If the facility is following that process they will likely be able to kill jumping worms and their eggs.
    • Clean soil off of your gardening gear (tools, gloves, shoes, carts, etc.) before taking it to another yard.
    • If you participate in garden club plant sales or informal plant exchanges, follow these recommendations:
      • Determine that the plants do not come from an area known to have jumping worms. Additionally, determine that there is no reason, like soil that looks like coffee grounds, to suspect there are jumping worms at the site that produced the plants.
      • Remove soil from all plants before transporting them as bare root plants or potting into sterile potting soil. This helps to remove earthworm cocoons (egg cases) and weed seeds.
      • View the University of Minnesota Extension full list of guidance on plant sale best practices related to jumping worms.
  • Vermicomposters:
    • If you purchase worms for composting, know how to identify the species you are buying.
    • Check your order to ensure it doesn’t have jumping worms in it.
    • Follow Great Lakes Worm Watch’s “ABCs of composting with earthworms safely”.
  • Recreationists:

Reporting

Report new occurrences of jumping worms to the DNR by contacting [email protected] or log in and submit a report through EDDMapS.

  • Take photos of the live worm. Researchers need high resolution, clear photos to identify jumping worms. Rinse off the worm so that it is free of soil. Place the worm on a plain surface such as a piece of cardboard or pavement (tan and gray backgrounds work better than white backgrounds). Make sure the photos are in focus and have a clear view of the ring around the body (clitellum) in relation to the head as researchers will count the body segments between the head and clitellum. Do not use the zoom feature on your phone as this decreases clarity of the photo. 
    • Jumping worms hatch from tiny eggs in the spring. They are immature and do not have the clitellum (ring) until late July. Researchers are not able to definitively identify worms that do not have a clitellum. Worms that are large and mature in the spring are likely other worm species, such as nightcrawlers (Lumbricus species).
  • Optional: Take a short video of the movement of the worm when touched.
  • If possible, keep the specimen, in case you need to take additional photos. Add alcohol to a small bottle, jar, re-sealable plastic bag, or plastic storage container. Place the worm inside and store in the refrigerator.

Control methods

Preventing the introduction and spread of jumping worms in Minnesota is more effective than controlling established populations. Do not purchase or import jumping worms, and remember to inspect mulch, plants, soil and bait for jumping worms.

There are no known methods for controlling invasive earthworms on a large scale in natural settings. Chemical treatments that would kill earthworms would kill beneficial soil organisms as well. Jumping worms live near the top of the soil surface and in the leaf and mulch layer. You can hand collect worms, seal them in a bag, and dispose of them in the trash. This may help reduce the amount of jumping worms at your site.

Gardeners have many questions about how the timing of gardening activities or how various soil amendments or mulches affect jumping worms. There may be garden management techniques that reduce the impacts of jumping worms, but we have little information on this. University of Minnesota Extension has collected gardener experiences and summarized the results on the Report Jumping Worm Management webpage.

Resources

Back to top