The effects of early season temperature on adult life history traits of wheat stem sawfly Cephus cinctus Norton (Hymenoptera: Cephidae) and Bracon cephi (Hymenoptera: Braconidae).

Wheat stem sawfly, Cephus cinctus Norton (Hymenoptera: Cephidae), is a long-standing pest of wheat Triticum aevstivum L. (Poaceae) in the northern Great Plains region of North America. Larval feeding damage within the wheat stems causes decreased head kernel weights, reduced photosynthetic capacity, and overall yield losses. Serious C. cinctus infestations can cause economic losses exceeding over $400 million annually. Recently, a bioclimatic model for C. cinctus was developed for the Canadian Prairie region, but the model lacks forecasting capabilities due to missing knowledge gaps of how early season weather patterns affect C. cinctus population dynamics. The purpose of the study was to measure the effects of different post-diapause development conditions on life history traits of adult C. cinctus. Field-collected individuals were reared under three different temperature regimes to generate distinct emergence groups for adult body size, successful emergence, longevity, lipid content, and egg capacity comparisons. With a better understanding of how early season weather can affect C. cinctus population dynamics, a forecasting model for C. cinctus can be developed.