Impact of Host Density on the Performance of the Bracon hebetor (Say) (Hymenoptera: Braconidae) Parasitizing Indian Meal Moth, Plodia interpunctella (Hübner) (Lepidoptera: Pyralidae)

Abstract

The parasitoid species Bracon hebetor (Say) (Hymenoptera: Braconidae) is an important beneficial insect as it can be used as a biological control agent. On the other hand, the Indian meal moth, Plodia interpunctella (Hübner) (Lepidoptera: Pyralidae) is a serious pest of stored and processed food products. The present work was conducted to investigate the impact of host density on the performance of the parasitoid and its next progeny for its mass rearing. The investigation indicates that there is no significant difference among the percentages of parasitized host larvae due to different host densities. However, the number of parasitoid pupae (P=.05), total number of adult emerged (P<.001), F1 larval periods (P<.001), F1 pupal period (P<.001), F1 total developmental period (P<.001), longevities (P=.05) differed significantly due to different host densities. Moreover, the experiment also showed that there are significant differences among the F2 larval periods (P<.001), total developmental period (P<.001), longevity (P=.05) but not among the number of F2 adult progeny, number of parasitized host larvae by F1 and number of F2 pupae. The results also showed no significant difference among the sex ratios of the F1 generation, F2 generation and size of parasitoid due to different host densities.