Parental effects: physiological age, mating pattern, and diapause duration on diapause incidence of progeny in the cabbage beetle, Colaphellus bowringi Baly (Coleoptera: Chrysomelidae)

The cabbage beetle, Colaphellus bowringi Baly, is a short-day species that has both a facultative summer and winter adult diapause. In this study, we systematically investigated the effects of parental physiological age, mating pattern (including mating frequency and delayed mating), and diapause duration on the diapause incidence of progeny in the beetle. As parents aged, progeny diapause incidences showed considerable inter-parental variability and an abnormally varying pattern, but their predicting line was approximate to horizontal when reared under constant conditions. There was significant difference in progeny diapause incidence between multiple-mating and once-mating treatments. Higher diapause incidences in the progeny were observed in delayed-mating treatments. Progeny diapause incidences increased as diapause duration in the parental generation increased, and hibernating individuals produced more diapausing progeny than aestivating ones. Reciprocal cross tests between the post-diapause adults and non-diapause adults with no diapause history showed that the effect of parental diapause duration on the progeny diapause incidence was determined by both mothers and fathers but the mothers appeared to have a stronger effect than the fathers. Our results suggest that the parental age effect in Colaphellus bowringi might not be simply age-dependent, but may be controlled by the interaction of multiple factors, including physiological, environmental, behavioral and genetic factors. We discuss the ecological and physiological significance of these findings.