Winter Stonefly

Natural Habitat

Near clean, cool streams and rivers with rocky substrates; often found on snow or bridges during winter.

Diet & Feeding

Larvae (nymphs) eat algae, detritus, and decayed vegetation; adults generally do not feed or may consume soft plant matter and algae.

Behavior Patterns

Unique for emerging and mating during the coldest months of winter; nymphs are aquatic and gills-based while adults are terrestrial.

Risks & Benefits

Harmless to humans; excellent biological indicators of high water quality and an important food source for fish like trout.

Identified on: 5/22/2026