Horsehair Worm
Scientific Name: Gordius robustus
Order & Family: Gordiacea; Gordiidae
Size: Typically 10 cm to 30 cm long, but can reach lengths of 1 meter; very thin (about 1 mm to 3 mm in diameter).
Natural Habitat
Found in freshwater environments such as streams, ponds, puddles, and livestock watering troughs; sometimes found on land after rain.
Diet & Feeding
As larvae, they are endoparasites of insects like crickets and grasshoppers, absorbing nutrients through their skin. Adults do not feed.
Behavior Patterns
Larvae develop inside an insect host. When mature, they influence the host's behavior, compelling it to jump into water where the worm emerges to mate and lay eggs.
Risks & Benefits
Harmless to humans, pets, and plants. Benefits the ecosystem by naturally controlling populations of crickets, grasshoppers, and beetles.
Identified on: 7/1/2026