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Caddisflies (Trichoptera)

To view caddisfly distribution maps, visit the Caddisfly Atlas page.

General Information about Caddisflies (Trichoptera)
Life history Caddisflies can spend from 2 months to 2 years as larvae in the water. They prepare a cocoon in the water during their pupal stage (before hatching into adults).
Diversity There are about 26 different families of caddisflies in North America.
Antennae are not visible; 3 pairs of segmented legs; no wing pads; head and first thoracic segment always has a hardened skin; pair of prolegs with one claw at end of soft abdomen; most larvae live in a portable case or retreat.
Habitat & Feeding Caddisflies live in a wide range of habitats, including cool streams, warm streams, lakes, marshes, and permanent or temporary ponds. Caddisflies feeding is diverse; taxa within the group use almost every type of feeding strategy: shredders (eat decaying plant material), scrapers (eat algae off rocks), collector-gatherers (eat fine organic material), collector-filterers (eat fine organic material collected from the flowing water), or predators.
Water quality indicator status Most types of caddisflies are pollution sensitive. Caddisflies are a good indicator of water quality because they live within a diversity of habitats. However, some types that are widespread, can tolerate pollution and environmental stress. Caddisfly larvae are part of the widely used EPT Index (Ephemeroptera-Plectoptera-Trichoptera) to measure water quality condition. It is the number of different types of mayflies, stoneflies, and caddisflies.
Fun facts
  • Caddisfly larvae make a silk thread that they use to build portable cases, stationary retreats, or nets to filter food particles from the water.
  • Cases serve as shelters and, in low oxygen environments, allow larvae to move water across their gills by undulating their bodies inside their case.
Image of caddisfly in the Hydropsychidae family.
Family: Hydropsychidae
Image of caddisfly in the Philopotamidae family.
Family: Philopotamidae

Image of a caddisfly in the Brachycentrus genus.
Brachycentrus sp.
Image of caddisfly in the Glossosoma genus.
Glossosoma sp.

Image of helicopsychidae
Family: Helicopsychidae
Image of hydroptildae
Family: Hydroptilidae

Image of odononceridae
Family: Odonoceridae
Image of polycentropodidae
Family: Polycentropodidae

Image of lepidostaomatidae
Family: Lepidostomatidae
image of uenoidae
Family: Uenoidae

image of Rhyacophilidae
Family: Rhyacophilidae