Limnology

Caddisflies (Trichoptera)

Little is known about the Trichoptera, or caddisflies, of Iowa. About 1,400 species can be found in North America with 64 species being found in Iowa (University of Iowa Hygienic Lab Collection List). The worldwide total is now greater than 12,600 species. When comparing the order Trichoptera to other insect orders, it is medium-sized in terms of diversity. However, it is the largest order of insects that is entirely aquatic. They can live in all types of lotic (flowing water) and lentic (standing water) habitats, including temporary bodies of water. The ability of caddisflies to live in these varied habitats and the great diversity of species can be attributed to their use of silk threads for producing portable or attached cases. These cases are usually made from wood, detritus or rock. This provides protection and camouflage within the environments in which they reside. Caddisfly larvae resemble caterpillars with jointed legs and can be distinguished from other aquatic insects by their hardened head capsule, short antennae, lack of wing pads and soft abdomen. Adults have two long antennae and wings covered with very short hairs held slanted or roof-like above the abdomen. The word Trichoptera is in reference to these hairy wings, the Greek "trich" meaning hair and "ptera" meaning wing.