Invasive Worms Eat Baby Plants

earthworms in the soil photo

Image credit: goosmurf/Flickr

Earthworms, it has long been thought, benefit plants by recycling nutrients—leading to richer soil for the plants to grown in. New research, however, has uncovered some unexpected—and potentially unsettling—worm behavior.

Instead of simply rejuvenating the soil, these studies have found, earthworms actually hunt for young plants and seeds—devouring them before they have a chance to poke through the surface.To study the worms' dietary preferences, researchers offered them a variety of seeds and seedlings. The noticed that the earthworms selectively fed on slow-germinating, nitrogen-rich seeds and seedlings. This behavior inevitably led to the death of the plant but the worms that were able to find these meals grew larger and performed better than those that did not.

For gardeners who see a clear benefit from increased earthworm activity, these findings could help them attract even more into their beds. Indeed, because of their important role in maintaining soil health, earthworms cannot in most cases be considered pests.

Still, when exotic worms enter non-native habitats, endemic plants may be unable to cope with the new predators. These recent findings support field observations that the introduction of earthworms is sometimes followed by the extinction of local plants.

Nico Eisenhauer, who led the study, explained:

The finding that earthworms function as seedling predators highlights the necessity to prevent the further anthropogenic spread of exotic earthworms.

Read more about invasive species:
The World's Most Lovable Invasive Species
The Iron Curtain Stopped Invasive Species
Eating Aliens: Are Invasive Species Ethical Food?
Read more about earthworms:
Mythic Giant Earthworm Not Extinct, Spitting, or Sweet Smelling
British Earthworms May Get Nudged Out by European Invaders Thanks to Climate Change
Invading Worms Menacing Hardwood Forests

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