Horsehair Worm

Scientific Name: Gordius robustus (and other Chordodidae species)

Order & Family: Order: Gordiida; Family: Gordiidae

Size: 5 to 100 centimeters long, but only 1 to 3 millimeters thick.

Found in freshwater environments such as troughs, ponds, streams, and puddles, often appearing after rain.

Adults do not eat; larvae are parasites that absorb nutrients from the body fluids of hosts like crickets and beetles.

Larvae infect insects and eventually manipulate the host's behavior to seek water; the adult worm then bursts out of the host to mate in water.

Harmless to humans, pets, and plants; beneficial as a natural control for certain insect populations such as crickets and cockroaches.

Identified on: 3/3/2026