Facts, Identification & Control
Caddisfly is a generic name given to the insects that belong to the order Trichoptera. There are approximately 1,200 U.S. species within this order, and some entomologists study caddisflies exclusively. The caddisfly is known by many names, including sedge, shadfly and periwinkle. Caddisflies belong to one of the most prolific orders in the animal kingdom.
Caddisflies are not actually flies. Flies belong to the order Diptera. Caddisflies belong to the order Trichoptera. Adult caddisflies are terrestrial, while larvae are aquatic and can be found in lakes, rivers, streams and other freshwater sources. Caddisflies form a very significant part of freshwater food chains, and the presence of these insects typically indicates that an aquatic ecosystem is healthy.
Adult caddisflies are similar in appearance to moths. They have minimized mouthparts and well-developed compound eyes. Although they live on land, adult caddisflies typically inhabit areas near freshwater sources in order to ease breeding processes.
Behavior, Diet & Habits
Caddisfly larvae are aquatic, while adults are terrestrial and visit water only to lay their eggs. Caddisflies serve an important role in upholding the ecological balance of freshwater sources, as fish feed on them. Caddisflies also help keep these bodies of water clean by feeding on fallen leaves and other detritus.
Caddisflies make shells or casings for their pupal stage. The type of materials used for caddisfly casings varies from species to species. Some use soil for casings, while other caddisflies use dead twigs and leaves.
Like many other insects, the complete life cycle of the caddisfly is comprised of four stages: egg, larval, pupal and adult. After mating, the female caddisfly skims the surface of a water source and deposits her eggs in strand-like formations. These eggs are a bright green in color and sink to the bottom.
Eggs eventually hatch into caddisfly larvae. Caddisfly larvae are grub-like in appearance and feed on detritus within the bodies of water they inhabit. Caddisfly larvae create strands of silk from their salivary glands. After feeding, caddisfly larvae begin to form casings used in the pupal stage. These cases are constructed of small rocks, twigs and other gathered materials.
Signs of a Caddisfly Infestation
Homeowners typically encounter only the adult stage of caddisflies. They may be seen gathering near lights, sometimes in large numbers, but are incapable of breeding and infesting indoors.