Abstract
To compare the life cycle trends of populations feeding on different host plants, two populations of the cucurbit-feeder ladybeetle, Epilachna admirabilis, were surveyed at Setagaya and Hadano, in and near Tokyo. Although both populations have a similar life cycle, the larval period of the Setagaya population feeding on Trichosanthes kirilowii was shorter than that of the Hadano population feeding on Gynostemma pentaphyllum and T. cucumeroides. A small part of the Setagaya population emerged in autumn, but all known conspecific populations emerge in spring. Laboratory rearing tests showed that larvae reared at 24°C, 16L-8D on T. kirilowii pupate 54 days after hatching, but those reared on G. pentaphyllum pupated 83 days after hatching. The life-cycle variation in E. admirabilis is caused, at least in part, by different availability of host plants. We also observed many adults sucking honeydew produced by the aphid Shivaphis celti when food plants were in scarce.
