Stonefly nymphs live exclusively in clean, well-oxygenated streams, which makes them one of the most reliable bioindicators of water quality in temperate ecosystems.

Adults emerge from the water, mate within hours or days, and many species do not feed at all. Their distinctive features include two pairs of membranous wings folded flat over the abdomen at rest and two long cerci at the tip of the body.

Plecoptera is a small order of about 3,500 species, but its dependence on cold, clean water makes individual species useful for tracking watershed health.