Horsehair Worm
Scientific Name: Nematomorpha
Order & Family: Order: Gordioidea; Family: Chordodidae (among others)
Size: Typically 10 to 70 centimeters long, but very thin (1-3 millimeters in diameter).
Natural Habitat
Adults are free-living in freshwater environments like puddles, troughs, streams, and wet soil. Larvae are parasitic inside terrestrial arthropods.
Diet & Feeding
Adults do not feed; they rely on stored energy. Larvae absorb nutrients directly through their skin while inside their insect hosts.
Behavior Patterns
Larvae parasitize insects like crickets, cockroaches, and grasshoppers. Upon maturing, they manipulate the host's behavior to seek water, where the worm bursts out to breed.
Risks & Benefits
They pose no risk to humans, pets, or plants. They are beneficial as they help control populations of pest insects like crickets and cockroaches.
Identified on: 2/27/2026