Stonefly

About the Stonefly

Excellent bioindicators - they can only survive in clean, well-oxygenated water. Their presence means a stream is healthy. Over 3,500 species. Their nymphs live 1-3 years underwater before emerging as adults that live only days. They are among the most primitive winged insects. Fly fishermen imitate them extensively. They are one of the first insects to emerge in spring. Some species are flightless. They are found on every continent except Antarctica. Their fossils date back 300 million years. They require cold, flowing water to survive. Pollution eliminates them from streams quickly.