Horsehair Worm (also known as Gordian Worm)
Scientific Name: Nematomorpha (Phylum)
Order & Family: Order: Gordioidea, Families vary (e.g., Gordiidae, Chordodidae)
Size: Typically 10 to 100 cm (4 to 40 inches) in length, but extremely thin (1-3 mm in diameter).
Natural Habitat
Adults are free-living in freshwater bodies like puddles, troughs, streams, and sometimes damp soil. Larvae are internal parasites of terrestrial arthropods like crickets and beetles.
Diet & Feeding
Adults do not feed; they rely on stored energy. Larvae absorb nutrients directly from their arthropod hosts.
Behavior Patterns
Known for the 'Gordian knot' behavior where multiple worms tangle together during mating. Most distinctively, they manipulate their host's behavior to seek water, causing the host to drown so the adult worm can emerge.
Risks & Benefits
Harmless to humans, pets, and plants. They are beneficial as they help control populations of pest insects like crickets, grasshoppers, cockroaches, and beetles.
Identified on: 3/2/2026