Habrobracon hebetor ectoparasitism paralyzing effect on Corcyra cephalonica of different instar larvae

Abstract

Corcyra cephalonica (Lepidoptera) is an important storage product pest that damages rice, corn and other grains. Habrobracon hebetor is a parasitic wasp that is capable of paralyzing lepidopteran pests. However, how C. cephalonica affects the prey preferences, fitness, and functional response of H. hebetor remains poorly understood. We therefore used selective and nonselective, age–stage two-sex life tables and functional response models to determine how this problem could be solved. Our results showed that H. hebetor preferred the 4th to last instar larvae of C. cephalonica and that its functional responses were consistent with the Holling II model in these three instars. However, the search ability of the 4th instar larvae was strong and its processing time was short. Additionally, generative development can be completed in the 4th to last instar larvae of C. cephalonica, whereas the 5th instar provided wasp predators with the best life history, population and paralysis rate parameters measured in this study. We also found that the wasp displayed its highest population size and total paralysis rate within 60 days on 5th instar larvae. Thus, we conclude that 5th instar larvae are a suitable host for H. hebetor. These results not only provide a theoretical reason to use H. hebetor to control C. cephalonica infestation but also broadens the known host larvae selection range for industrial production of this parasitic wasp.