Life history traits of pest and non-pest populations in the phytophagous ladybird beetle, Epilachna niponica (Coleoptera, Coccinellidae).

摘要

Life history traits of Epilachna niponica were compared between a non-pest population feeding on wild thistle (Cirsium) and a pest population feeding on cultivated solanaceous crops, mainly potato, in Japan, during 1985. The pest population had larger females, a higher population growth rate, more continuous oviposition, and a shorter developmental period in the immature stages, than the non-pest population. The two populations showed no clear differences in phenology from spring to autumn, egg mass size, hatchability, and larval survival rate. Significant differences were found in number of eggs laid per female during the first and second periods, and in the developmental period of the immature stages. These life history traits were influenced primarily by food plant. A higher fecundity and shorter immature period appear to be readily altered by the host shift from thistle to potato.