Horsehair Worm
Scientific Name: Gordius robustus (and other Chordodidae species)
Order & Family: Order Gordiida, Family Gordiidae or Chordodidae
Size: 5 to 100 centimeters in length, but only 1 to 3 millimeters in diameter.
Natural Habitat
Freshwater environments such as ponds, streams, puddles, and water troughs, often emerging from terrestrial host insects near water.
Diet & Feeding
No adult feeding; larvae are parasites that absorb nutrients from the body cavity of host insects like crickets, grasshoppers, and beetles.
Behavior Patterns
They are parasitic as larvae. Once they reach maturity, they influence the host's behavior to seek out water, where the worm will then emerge to mate and lay eggs.
Risks & Benefits
Completely harmless to humans, pets, and plants. They provide an ecological benefit by naturally controlling populations of crickets, cockroaches, and grasshoppers.
Identified on: 1/11/2026