Parasitic functional response and offspring development performance of Meteorus pulchricornis on different instars of Ostrinia furnacalis

To evaluate the parasitic potential of Meteorus pulchricornis (Wesmael) on Ostrinia furnacalis, the parasitic functional response, searching efficiency, and offspring development of M.pulchricornis on the 3^rd and 4^th instar larvae of O. furnacalis were studied under laboratory conditions. The results showed that the parasitic functional responses of M.pulchricornis to different instar larvae of O.furnacalis conformed to the Holling Ⅱ model. Regarding parasitism performance on hosts of different instars, both the parasitic efficacy and searching efficiency on 3^rd instar larvae were higher than those on 4^th instar larvae. The results of offspring development from different instars showed that the host instar significantly affected the offspring's larval development duration and pupal duration. The larval duration (10.72 d) and pupal duration (6.09 d) of offspring wasps that developed from the 4^th instar hosts were significantly longer than those of the 3^rd instar larvae. Nevertheless, the host instar had no significant effect on the pupation rate and adult eclosion rate of offspring larvae. These findings suggest that M. pulchricornis exhibits higher parasitic efficacy against 3^rd instar larvae of O. furnacalis, but parasitizing older (larger) larvae may result in higher fitness of the offspring.