Also called ‘sedges’ or ‘sedge flies’, caddisflies are often mistaken for moths, and are often caught in moth traps. Belonging to the order of insects called Trichopera, this group of insects are often overlooked for their dull appearance, yet they are most interesting, and some can be quite beautiful in their own way. There are about 7000 species worldwide, and 198 in Britain. Fossils of Caddisflies have been found as far back as the Cretaceous, and maybe the Jurassic, which may have been an ancestor of Trichoptera and Lepidoptera.
Caddisflies breed and live in and around freshwater habitats like streams, rivers and ponds. The adults are mainly seen by the human population in gardens, attracted to bright lights, or caught in moth traps, which suggests they are nocturnal. They are medium-sized insects bristling with hairs, which hold their wings close to the body in a tent like fashion. They have very long antennae. The larvae are well-known to fishermen when fly-fishing. They are aquatic with gills for breathing underwater, and most live in a protective case made from all kinds of natural materials like vegetation, gravel and sand, and even mollusc shells. Some live in silk tubes They live under rocks or amongst weed beneath the water. They go through various stages and when they molt they have to build a new case. Trichoptera have biting mouth parts, whilst some are strict herbivores eating only plant material, others are carnivores or omnivores.
They hold an important place and play a vital role in the environment of these freshwater habitats, where they provide food for fish and birds.
Caddisflies can be very hard to identify as many look similar and require microscopic scrutiny regards to wing venation and genitalia to mark the differences which aid in identifying individual species.