Skip to content
Chesapeake Bay Program

Caddisflies

Caddisflies are moth-like insects that are attracted to lights at night and live near lakes or rivers. They are popular food for fish and often used in fishing.

Quick Facts

Species Type

Native

Size

Adult caddisflies are commonly 3 to 15 millimeters (0.1 to 0.6 inch) in length

Habitat

Variety of aquatic habitats, from small ponds and streams to large lakes and rivers; can survive a wide range of water quality conditions including slightly degraded or polluted streams

Diet

Ranges from bacteria to plants to other insects, depending on the species

Lifespan

Most of a cadisifly’s life cycle is spent in the larval stage and the adults are generally short lived.

Conservation Status

Stable
Caddisflies have long antennae and are usually hairy, with hairs and/or prominent veins on two pairs of wings. Above, a black dancer caddisfly in Fairfax County, Va. (Photo courtesy of ndebarros/iNaturalist CC BY-NC)

Appearance

Caddisflies are similar to moths in appearance and the larvae have elongated bodies resembling caterpillars of moths and butterflies. Adults are characterized by four wings that bear hairs on the membrane or prominent veins, or both. The head and thorax are also usually hairy. The antennae are long and slender and are usually about the length of the anterior wing.

Feeding

Most larvae feed on aquatic plants, algae, diatoms, or plant debris. A few eat other aquatic insects, crustaceans, and mollusks. Most adult caddisflies are incapable of feeding on solids and instead suck nectar from flowers.

Predators

Caddisfies are an important food source for many predators, including Atlantic salmon, brown trout, birds and bats.

Reproduction and Life Cycle

Caddisflies undergo complete metamorphosis. Their life cycle includes four stages – egg, larva, pupa and adult. Most species produce one generation per year.

Did You Know?

  • Caddisflies are closely related to moths (order Lepidoptera), which they are often mistaken for.
  • As like in moths, caddisflies are active at night and attracted to light (representing important food source for bats).
  • Caddisflies can produce cases for larvae, typically built out of sand, rock, twigs, leaf pieces, and any other kind of underwater debris.
  • The word Trichoptera is in reference to the insect's hairy wings, the Greek "trich" meaning hair and "ptera" meaning wing.

Sources and Additional Information

Tags:
Insects Invertebrates Arthropods Streams & Rivers Open & Shallow Waters