Trichoptera

Definition

An order of holometabolous insects comprising the caddisflies, characterized by adults with two pairs of hairy (setose) membranous wings and larvae that are almost exclusively aquatic. Distinguished from the related order Lepidoptera by the presence of hairs rather than scales on wings; together these orders form the superorder Amphiesmenoptera. Larval ecology divides the group into case-makers (Integripalpia), which construct portable shelters from silk and environmental materials, and retreat-makers (Annulipalpia), which spin fixed filter-feeding nets.

Etymology

From Greek tricho- (hair) + ptera (wings), referring to the hairy wings of adults.

Example

The larvae of the caddisfly Limnephilus lunatus (family Limnephilidae) build spiral cases from sand grains and plant fragments, dragging them along streambeds as they graze on periphyton.

Synonyms

• Caddisflies
• caddises
• sedge-flies

Related Terms

• Amphiesmenoptera
• Lepidoptera
• Integripalpia
• Annulipalpia
• aquatic insect
• holometabolous

Usage Notes

The common name 'caddisfly' (or 'sedge-fly' in angling contexts) refers to adults; 'caddis' alone often denotes the larval stage, especially among anglers and aquatic ecologists. The order contains approximately 14,500 described species globally, with larval stages serving as important bioindicators of freshwater quality. Spelling variants 'Trichoptera' (order) should not be confused with the dipteran genus Trichoptera Meigen, 1803 (winter crane flies).