Abstract:  To gain insights into mechanisms of superparasitization in Meteorus pulchricornis (Wesmael), dual-choice tests were performed to observe preferences of the parasitoid between healthy and parasitized hosts, Prodenia litura (Fabricius) (healthy∶parasitized 2nd instar larvae=5∶5), as affected by parasitization experiences (three levels: no parasitization experience, parasitization once, superparasitization once) and interval-time (1-7 d) elapsed after single parasitization; a repeated measures design was exercised to observe oviposition stings during three successive visits to host patches of different quality as measured by the proportion of parasitized hosts (2, 5, and 8 parasitized hosts among 10 hosts, respectively) in a patch. The analysis results of preferences showed that the probability of superparasitization was significantly affected by parasitization experiences of parasitoids and time interval after single parasitization, and it was decreased with the time interval and parasitization experience. The Cox model was fitted to the discrimination time prior to oviposition, and the results indicated that the hazard of superparasitization diminished both with extending of the interval time after single parasitization and with the parasitoid experience of superparasitization. The trials on parasitization during visits to host-patches of different qualities showed that the number of oviposition stings increased with the quality of host patch. The results suggest that M. pulchricornis can discriminate not only parasitized hosts, but also host patches with single parasitized hosts.

Key words: Meteorus pulchricornis, parasitization behavior, superparasitization, learning, host discrimination, discrimination time, host patch quality