Capniidae

Definition

A family of small winter stoneflies in the order Plecoptera, comprising approximately 300 species distributed across the Holarctic region. Capniidae are distinguished by their winter-emergence phenology, small body size, and reduced wing venation compared to other stonefly families. Adults typically emerge during cold months when air temperatures are near freezing, often walking on snow to reach streams for mating and oviposition. The family represents one of the largest stonefly families and is sister to Leuctridae (rolled-winged stoneflies).

Etymology

Example

Capnia nana, a widespread Capniidae species in western North America, emerges in mid-winter and is frequently collected by snow-shoveling entomologists searching for active adult insects on streamside snowbanks.

Synonyms

• Small winter stoneflies

Related Terms

• Plecoptera
• Leuctridae
• winter stonefly
• emergence phenology
• aquatic insect

Usage Notes

The common name 'small winter stoneflies' reflects both the diminutive size (most adults under 10 mm) and the unusual cold-season emergence pattern that distinguishes this family from most Plecoptera, which emerge in spring or summer. Capniidae larvae are typically found in the hyporheic zone or surface waters of small, cold streams. The family is sometimes called 'snowflies' in older literature, though this term is ambiguous and best avoided.