One-host one-parasitoid system: Population dynamics of a zygaenid mothPryeria sinica Moore in an undisturbed habitat

Summary The population dynamics ofPryeria sinica was investigated in an undisturbed area in 1976–1979. We analyzed the process stabilizing the local population by the life table approach for immature stages and the mark-recapture method for the adult stage. Females usually layed about 130 eggs in an egg-mass. The shape of the survivorship curve was convex and was characterized by a relatively low mortality in the egg and larval stages and by a relatively high mortality in the prepupal and pupal stages. The low mortality in the early stage seemed to be not only due to the peculiar life cycle of this species (larvae develop in early spring when natural enemies are not active) but due to their protective nest-webs, larval warning coloration and repellent smell. The high mortality after cocooning was caused by severe parasitization byAgrothereutes minousubae. The number of adult in the population varied by 2.10-fold, which was less than that of other gregarious moths. The life table data and field observations suggest that adult female dispersal would have acted as a stabilizing factor, andA. minousubae as a conditioning factor on the dynamics of the moth population.