Horsehair worm

Natural Habitat

Aquatic environments (ponds, puddles, troughs) as adults; parasitic in arthropod hosts (crickets, grasshoppers, mantids, beetles) as larvae and juveniles

Diet & Feeding

Adults do not feed; larvae are parasitic, absorbing nutrients from their arthropod host.

Behavior Patterns

As larvae, they develop inside an invertebrate host. When mature, the worm manipulates the host's behavior, causing it to seek water and drown itself, allowing the adult worm to emerge and live freely in the water to reproduce. They are noticeable as tangled masses in water.

Risks & Benefits

Generally harmless to humans and pets, as they are not parasitic to vertebrates. Can be beneficial in controlling populations of some pest insects. Their appearance can sometimes be alarming due to their unusual length and movement.

Identified on: 10/7/2025