Reproduction and quality of F1 offspring in Chrysoperla carnea: Differential influence of quiescence, artificially-induced diapause, and natural diapause

Abstract

We asked how physiological status during cold storage might influence the subsequent reproduction of mass-produced Chrysoperla carnea adults and the quality of their F1 offspring. To achieve an answer, we examined the performance of adults and their offspring after adults experienced three treatments: cold-induced quiescence under constant low temperature, artificially induced diapause followed by constant low temperature, and natural diapause out-of-doors. Physiological state did not affect survival during and after storage under constant low temperature, but during extremely cold winter conditions, the naturally overwintering adults suffered significant mortality. Cold-induced quiescence resulted in a slight loss of post-storage reproduction (lower incidences of fertile oviposition and decreased fecundity and lifetime fertility), as well as reduced rates of survival and development in F1 offspring. In contrast, adults that were either stored in an artificially induced diapause or overwintered naturally out-of-doors, exhibited sustained high levels of post-diapause reproduction and they produced high-quality F1 offspring. Overall, storage of diapausing adults under constant low temperature resulted in both high survival and high levels of post-storage reproduction. Unstored, nondiapause pairs had significantly poorer reproductive performance and lower quality F1 offspring than cohorts that underwent storage in a state of diapause. These data and other data from C. carnea adults collected early and late in the season indicate that the occasional intervention of diapause may help prevent deterioration of stock during continuous rearing of this predator.