Diapause incidence of progeny in relation to parental geographic origin, host plant and rearing density in the cabbage beetle, Colaphellus bowringi

Abstract

AbstractThe cabbage beetle, Colaphellus bowringi Baly (Coleoptera: Chrysomelidae), which is widely distributed in China, undergoes an imaginal diapause in the soil. In this study, we investigated the influences of parental geographic origin, host plant, and rearing density on the diapause incidence of progeny in this beetle. In studies conducted at 25 °C and L12:D12 photoperiod, the proportions of adults entering diapause were significantly different among latitudes from which the parents had been collected. The incidence of diapause increased with increasing latitude. Reciprocal cross tests between post‐diapause adults from different latitudes showed that there were significant differences in diapause incidence between pure‐bred and hybrid adults, suggesting that diapause incidence among progeny was determined by both the female and male, although the female appeared to have a stronger effect than the male. These results revealed that parental origin has an important influence on progeny diapause. Parental host plant species not only affected diapause incidence of the current generation, but also affected the incidence of diapause in the progeny produced by the non‐diapause parents; yet, the parental host plant had no influence on the incidence of diapause in the progeny produced by the post‐diapause parents. Rearing density of the parental generation had no significant effect on the incidence of diapause in the progeny.