Host suitability and fitness-related parameters of Cotesia glomerata L. (Hymenoptera: Braconidae) on different instars of Ascia monuste orseis Godart (Lepidoptera: Pieridae)

ABSTRACT: The study aimed to adapt the instar of host Ascia monuste orseis to the parasitism of Cotesia glomerata and evaluate the parasitoid performance. Females of C. glomerata were exposed to 2nd, 3rd, 4th and 5th instars larvae of A. monuste orseis , allowing parasitism for two hours. Subsequently, the development of caterpillars that were fed with leaf sections of kale was monitored. The duration of each caterpillar instar, the weight of four days-old pupae, the percentage of parasitized caterpillars and mortality were assessed. Despite parasitoids, the following parameters were assessed: percentage of parasitism; number of parasitoids per host; percentage of emergence, sex ratio; average weight of the pupae, number of parasitoids per caterpillar; period egg-pupae; pupal period; and period egg-adult. The results indicated that the second instar of host A. monuste oreseis is the most suitable for the parasitism of C. glomerata for providing highest percentage of parasitism and a larger number of offspring per host.摘要：本研究旨在探究寄主Ascia monuste orseis的龄期（instar）对Cotesia glomerata寄生（parasitism）的适配性，并评估该寄生蜂（parasitoid）的寄生效能。将Cotesia glomerata雌蜂与Ascia monuste orseis的2、3、4、5龄幼虫共同放置，使其获得2小时的寄生机会。随后，对取食羽衣甘蓝（kale）叶段的幼虫发育情况进行监测。本研究测定了各龄幼虫的发育时长、4日龄蛹的重量、寄生幼虫占比及死亡率。此外，本研究还对以下寄生蜂相关指标进行了测定：寄生率、单寄主寄生蜂数量、羽化率、性比（sex ratio）、蛹平均重量、单幼虫寄生蜂数量、卵至蛹期、蛹期（pupal period）及卵至成虫期。研究结果表明，寄主Ascia monuste orseis的2龄幼虫最适配Cotesia glomerata的寄生，其寄生率最高且单寄主产生的子代寄生蜂数量最多。