Species Insects & ArthropodsWinter Stonefly

Winter Stonefly

Allocapnia pygmaea

CommonInsect & Arthropod
Illustration of Winter Stonefly (Allocapnia pygmaea)

The Winter Stonefly is a tiny, dark stonefly that emerges as an adult in winter, often crawling across snow on mild days — making it one of the few insects active in the coldest months. These early emergers allow mating before stream-bank vegetation leafs out, reducing predation risk. Ice fishermen often observe them at the edges of frozen streams.

Habitat
Rocky streams and rivers, active in winter
Diet
Nymphs: algae and diatoms. Adults: little or no feeding
How common
Common

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