Stoneflies, mayflies and caddisflies - river flies

This category includes several groups of insects which spend most of their lives as larvae on the beds of our rivers and lochs. They are an essential part of this environment providing a food supply for fish and birds such as the dipper.

Mayflies are some of the oldest winged insects known dating from over 300 million years ago. There are around 3050 species known from the World. Mayflies are the only insects to have two winged adult stages. 51 species know from the British Isles.

Stoneflies are a small group of aquatic insects, which generally prefer stony, fast flowing streams. There are 34 British species, including one species, the Northern February red (Brachyptera putata) which is only found in Scottish watercourses.

The Trichoptera, or Caddisflies, are an order of insects, which resemble moths, and of which there are just under 200 species in the British Isles. The name means 'hairy-winged', and indeed they differ from moths in having hairs rather than scales on their wings, amongst other differences.

Riverflies are vulnerable to pollution but Scotland has a high proportion of very clean waters.