Cosumnoperla hypocrena

Cosumnes Stripetail

Family: Tettigoniidae · Class: Insecta · Order: Plecoptera

Conservation status: G2 S2

The Cosumnes Stripetail is an aquatic insect in the order Plecoptera (stoneflies), family Tettigoniidae. This species belongs to the genus Cosumnoperla, which is endemic to California's Sierra Nevada foothills. Adult stoneflies are typically characterized by two pairs of membranous wings, long antennae, and cerci (tail-like appendages), though specific morphological details for C. hypocrena have not been extensively documented in available literature. Cosumnoperla hypocrena is endemic to California, with its distribution historically centered in the Sierra Nevada foothills of the Central Valley. The species' common name references the Cosumnes River drainage system, which likely represents a significant portion of its historical range. Current distribution data suggests the species may have experienced range contraction from its historical extent, though comprehensive surveys are needed to determine precise boundaries. Like other members of the Tettigoniidae family, C. hypocrena inhabits cold, flowing water systems (NatureServe Explorer). Nymphs require well-oxygenated streams with rocky or gravelly substrates typical of foothill environments. The species likely depends on specific water temperature regimes and flow patterns characteristic of Sierra Nevada tributaries. Adults emerge from aquatic environments but remain in riparian areas near their natal streams for mating and egg-laying activities. The life cycle of C. hypocrena follows the typical stonefly pattern of incomplete metamorphosis. Nymphs develop in stream environments, feeding on organic matter and potentially small invertebrates. Development time from egg to adult likely spans one to several years, depending on water temperature and food availability. Adults emerge during specific seasonal periods, though exact timing for this species has not been well documented. Mating occurs near streams, with females depositing eggs in or near water. Cosumnoperla hypocrena carries a Global/State conservation rank of G2 S2, indicating the species is imperiled both globally and within California due to rarity and vulnerability to extinction. This ranking reflects significant conservation concern, as G2 species typically have 6 to 20 occurrences or few remaining individuals. The species faces threats common to Sierra Nevada aquatic ecosystems, including habitat alteration from water diversions, sedimentation from land use changes, climate change impacts on stream flow and temperature regimes, and potential effects from introduced species. The limited scientific literature available for C. hypocrena reflects the broader challenge of studying endemic invertebrate species with restricted ranges. Stream habitat protection, water quality maintenance, and watershed-level conservation planning are essential for this species' persistence. The species' apparent rarity and specialized habitat requirements make it particularly vulnerable to environmental changes affecting Sierra Nevada foothill stream systems. This species is included on the California Department of Fish and Wildlife's Special Animals List. Further research is needed to determine current population status, precise habitat requirements, and specific conservation needs for this endemic California stonefly.

Data from The California Species Project — 14,000+ California species with verified data from CNPS, CDFW, USFWS, and more.