Abstract: A. Introduction

1. Ecological Importance

Aquatic insects are important components of lake and stream biota.^1–3 In trout streams, for example, they may comprise 50% to 90% of the macroinvertebrate species. Mayflies, stoneflies, caddisflies, midges, and other aquatic insects are major food items for many species of fish,^1,4 and many insect species play key functional roles in aquatic systems, including decomposition, organic matter processing, and nutrient spiralling.⁵