Jumping worms are part of a large group of Pheretimoid earthworms which are benign in their native soil but are an invasive species in North America. Three types of jumping worms, formally Amynthas agrestis, Amynthas tokionesis and Metaphire hilgendorfi tend to appear together in a resource-sharing co-invasion that out-competes other species and can leave entire forest ecosystems in a collapsed state. They are a new invasive in Canada and were first sighted in 2014. Unlike the common earthworm you might find in your garden, jumping worms are a serious threat to North American green spaces and forests. Named for their thrashing and "jumping" behaviour when disturbed, these worms devour soil substrate at a very fast pace. Jumping worms can rapidly change the structure of soil, causing damage that makes it much harder for less deep-rooted plants to hold on and for seeds to regenerate, while also causing erosion and a disturbed setting where invasive plant species more quickly move in.

Description:

 Color: Typically a dark purplish-grey with a milky-white band at the 14th segment from the head.

 Size: Ranges from 4-20 cm, depending on species.

 Jumping worms are distinguished by their glossy, smooth bodies and their thrashing, snake-like movement. Unlike other worms, they are very aggressive in consuming organic matter.

Key Effects on Soil:

Jumping worms are destructive to soil and forest substrate, consuming vast amounts of organic matter and breaking down leaves and mulch with alarming speed (Nouri-Aiin & Görres, 2024). This aggressive feeding cycle collapses the natural nutrient cycling process and destroys the soil structure, leading to a depleted substrate where native understory species struggle to survive (Cassin & Kotanen, 2016; Skinner et al., 2018). As a result of their impact, the health of the entire forest is compromised—harming wildlife, birds, insects, and the vital biota connected to the substrate layer (Bal et al., 2018).

When this process leads to the biological replacement of native plants with invasive species that thrive on the high-nitrogen, disrupted soil environment, the ecosystem is termed "collapsed" (Moore et al., 2018). While an invaded forest may appear to have a lush understory at first glance, the presence of largely non-native species is a definitive sign that the original ecosystem has been hijacked and its foundational processes—such as carbon sequestration and natural recruitment—have failed (Lejoly & Quideau, 2023); Chang et al., 2021).

References/Links:

Bal, T. L., Jurgensen, M. F., Richter, D. L., & Storer, A. J. (2018). Evidence of damage from exotic invasive earthworm activity was highly correlated to sugar maple dieback in the Upper Great Lakes region. Biological Invasions, 20(1), 151–164. https://doi.org/10.1007/s10530-017-1523-0

Cassin, C. M., & Kotanen, P. M. (2016). Invasive earthworms as seed predators of temperate forest plants. Biological Invasions, 18(6), 1567–1580. https://doi.org/10.1007/s10530-016-1101-x

Chang, C.-H., Bartz, M. L. C., Brown, G. G., Callaham, M. A., Jr., Cameron, E. K., Dávalos, A., Görres, J. H., Görres, S., & Szlavecz, K. (2021). The second wave of earthworm invasions in North America: Biology, environmental impacts, and prospects for management of invasive species in the family Megascolecidae. Biological Invasions, 23(10), 3291–3322. https://doi.org/10.1007/s10530-021-02598-1

Hamilton Conservation Authority. (2023). All about invasive jumping worms. Retrieved from https://conservationhamilton.ca/blog/ all-about-invasive-jumping-worms/

Invasive Species Centre. (2026). Jumping worms. Retrieved from

https://www.invasivespeciescentre.ca/invasive-species/meet-the-species/ land-and-animal-invertebrates/jumping-worms/

Lejoly, J., Quideau, S. A., & Laganière, J. (2021). Invasive earthworms affect soil morphological features and carbon stocks in boreal forests. Geoderma, 404(Part 1), 115262. https://doi.org/10.1016/j.geoderma.2021.115262

Nouri-Aiin, M., & Görres, J. H. (2024). Invasive earthworms and ecosystem processes in North America.Springer. DOI:10.1007/978-3-031-64510-5_1

Moore, J.-D., Ouimet, R., & Reynolds, J. W. (2018). Exotic Asian pheretimoid earthworms (Amynthas spp., Metaphirespp.): Potential for colonisation of south-eastern Canada and effects on forest ecosystems. Environmental Reviews, 26(1), 113–120. https://doi.org/10.1139/er-2017-0066

Skinner, M., et al. (2018). Do invasive worms threaten Northeast maple forests? The Maple Digest. https://mapleresearch.org/pub/m0218worms/