Horsehair Worm
Scientific Name: Gordius robustus (representative of the Phylum)
Order & Family: Order Gordioidea, Family Gordiidae
Size: Typically 10 to 35 centimeters (4 to 14 inches) long but very thin (about 1 to 3 millimeters).
Natural Habitat
Found in freshwater environments like ponds, streams, and puddles, as well as damp soil and occasionally inside houses reaching from their insect hosts.
Diet & Feeding
As adults, they do not eat. As larvae, they are internal parasites of insects such as crickets, grasshoppers, and beetles, absorbing nutrients through their skin.
Behavior Patterns
They have a complex life cycle where larvae grow inside a terrestrial insect host; they then manipulate the host's behavior to seek water, allowing the mature worm to emerge in an aquatic environment to mate and lay eggs.
Risks & Benefits
They are harmless to humans, pets, and livestock. They are considered beneficial to ecosystems because they help control populations of insects like crickets and cockroaches.
Identified on: 2/8/2026