Horsehair Worm

Scientific Name: Gordius robustus (and other Chordodidae/Gordiidae species)

Order & Family: Order: Gordiida, Family: Gordiidae

Size: Typically 4 to 14 inches long (10 to 35 cm) but very thin (approx. 1/25 inch wide).

Horsehair Worm

Natural Habitat

Found in damp areas, puddles, streams, and cisterns; larvae are internal parasites of insects.

Diet & Feeding

Adults do not feed; larvae are parasitic and absorb nutrients through their body wall from hosts like crickets and beetles.

Behavior Patterns

They are known for 'mind control' of their insect hosts, forcing them to jump into water so the adult worm can emerge to mate. When out of the host, they often knot themselves into Gordian knots.

Risks & Benefits

Harmless to humans, pets, and plants. They help control populations of nuisance insects like crickets and grasshoppers.

Identified on: 4/19/2026