Horsehair worm

Found in freshwater environments like ponds, streams, puddles, and troughs. Adults are aquatic, but larvae are internal parasites of terrestrial insects.

Larvae are parasites that absorb nutrients from the bodies of host insects (like crickets, beetles, or grasshoppers). Adults do not eat as they lack functional digestive tracts.

The worm manipulates its insect host's behavior to make it seek water. Once the host is in water, the adult worm emerges to mate, often twisting into complex 'Gordian knots'.

They are harmless to humans, pets, and plants. They are beneficial to the ecosystem by helping to control populations of certain insects like crickets and grasshoppers.