Caddisfly larvae may be case builders, net-spinners or free living. The use of silk for case building has allowed the caddisflies to become more diverse ecologically. Cases provide camouflage and protection from predators. Adult caddisflies look similar to small moths. Feeding Depending on the species, larvae may be filter feeders, herbivores or predators.
Adults feed on plant nectar if they feed at all.
When ready to pupate, the larva will construct a retreat or seal itself in the larval case which it anchors to the substrate with silk. The pupal stage lasts 2 to 3 weeks in most species while the adults generally live one month or less. The average life cycle is one year. Over half of all known species of aquatic insects are Dipterans and an estimated 3,500 or more species of aquatic and semi-aquatic Diptera live in North America. The larval stage can be found in almost every aquatic habitat, including hot springs.