Small winter stoneflies

Definition

A family of stoneflies (order Plecoptera) characterized by small body size, reduced or absent wings in many species, and adult emergence during winter months when temperatures are near freezing. Members of Capniidae are among the few insects active in cold conditions, often found crawling on snow or ice near streams. Many species are brachypterous or apterous, particularly in females.

Etymology

From the family name Capniidae (Greek kapnos, 'smoke,' referring to their habit of emerging from streams in winter when mist rises) and their small size and seasonal activity period.

Example

The western snowfly (Capnia nana), a small winter stonefly common in Pacific Northwest streams, mates and oviposits on snow-covered banks while air temperatures remain below 5°C.

Synonyms

• Capniidae

Related Terms

• Plecoptera
• stonefly
• brachypterous
• winter-emergent insects
• lotic insects
• cryophilic insects

Usage Notes

Used as a vernacular collective term for family Capniidae; not a formal taxonomic rank. Distinguish from 'winter stoneflies' broadly, which may include other cold-active Plecoptera. The common name reflects both size (typically 5–10 mm) and phenology (adults active November–March in temperate regions). Some species are fully winged, but aptery and brachyptery are common, particularly in females, making them easily overlooked in standard aquatic insect surveys.