ABSTRACT
The most familiar aquatic insects are those which live in the water of lakes, ponds, slow flowing streams, and small pools of water on wetlands. In standing and slowly flowing water, eutrophication makes survival harder for the insect species breathing through gills. So does contamination of the water with certain substances that interfere with the gas exchange. Food of the larvae often consists of microorganisms. Prominent among the dipterans that remain on the underside of the surface tension layer as larvae are members of the family Culicidae, which are strong swimmers as both larvae and pupae. Among the most abundant aquatic insects that live as predators in standing water bodies are those that swim rapidly and are able to catch their prey while swimming in the water column. The family encompasses relatively few species. Many of them are eliminated by pollution, after which the water column is dominated by insects that carry a supply of atmospheric air with them.
