Caddisflies are the order of insects known as Trichoptera which have aquatic larvae and terrestrial adults. There are many species of Caddisfly with 200 species commonly found across the UK. The adults inhabit almost all wetland habitats and the larvae are found in freshwater habitats such as rivers and streams where they remain in the larval form for up to 2 years before pupation. The larvae feed on decaying plant tissue and algae such as diatoms that they scrape off of rock. Some species are predacious and eat other animals. When ready to pupate they form their pupa out of sand, stones, twigs and leaves that they wrap in silk.