Life history and production of the riffle beetle, Stenelmis crenata (Say, 1824) (Coleoptera : Elmidae), in a tallgrass prairie stream

摘要

We examined life history dynamics and estimated production of the riffle beetle, Stenelmis crenata (Say, 1824), in a tallgrass prairie stream. Stenelmis crenata had a univoltine life cycle with larvae present year-round. Recruitment of first instars occurred from June-October, larval growth was synchronised through the winter, pupation occurred in late spring, and adults first appeared in late May. Adults were most abundant (24 individuals/m(2)) during summer and were present in samples through October. For larval biomass and production estimates, a body length-mass relationship (ash-free dry mass [AFDM]=0.0079*TL2.7595) was constructed. Mean annual density and biomass of larvae were 235 individuals/m2 and 90.7 mg AFDM/m(2), respectively. Annual larval production was 493mg/m(2)/y, representing a total of 101g AFDM for the stream reach examined. Production estimates for S. crenata in this stream were high compared to other estimates for elmids, and this species comprised an appreciable portion of total scraper (13.5%) production.