Comparative Analyses on the Parasitic Ability and Reproductive Strategy of Cotesia chilonis Based on the Events of Exposure to Hosts

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ABSTRACT Parasitoid wasps can parasitize many hosts in their lifetimes, but their level of parasitism varies with age. Therefore, it is particularly important to understand the fitness of parasitoids at different times in their life. We clarified the reproductive strategy of Cotesia chilonis (Munakata) (Hymenoptera: Braconidae) by studying the relationship between parasitic ability and factors, such as the upper longevity limit and events of exposure to hosts. Furthermore, we also studied the effects of the number of host exposures on the parasitic characteristics of offspring. We found that when host numbers were unlimited, the longevity of C. chilonis was significantly reduced compared to when parasitoids were not exposed to hosts. Besides, C. chilonis could survive and complete parasitization over six events of exposure to hosts (lasting up to 12 h each) over their lifetimes, and that the parasitization rate was higher in the first four events of exposures to hosts ranging from 77.5% to 92.5%. The body size of the female offspring (F 1 ) of parasitoids (P 1 ) with different bouts of parasitism varied and was positively correlated with the number of offspring in the following generation (F 2 ). Overall, the period within 12–24 h after eclosion of C. chilonis adults is most suitable for its mass rearing. For this age group, offspring had the highest quality indicators, including high fecundity, a high proportion of females in their progeny, and long lifespans. This study provides information on the reproductive pattern of C. chilonis useful for optimizing large‐scale breeding of this parasitoid.

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