Horsehair worm

Scientific Name: Gordius robustus (and other Chordodes species)

Order & Family: Order: Gordiida, Family: Gordiidae

Size: 10 to 35 centimeters in length, but only 1 to 3 millimeters in diameter.

Horsehair worm

Natural Habitat

Found in damp areas like soil, puddles, stream banks, and water troughs; adults are aquatic while larvae are internal parasites.

Diet & Feeding

Larvae are internal parasites that absorb nutrients from the bodies of insects like crickets or grasshoppers; adults do not feed.

Behavior Patterns

Larvae develop inside an insect host, eventually manipulating the host's behavior to seek water; once in water, the adult worm emerges to mate, often twisting into complex 'Gordian knots'.

Risks & Benefits

Harmless to humans, pets, and plants; they provide an ecological benefit by naturally controlling populations of pest insects like crickets and cockroaches.

Identified on: 3/23/2026