Reproductive performance of the parasitoid Bracon hebetor Say (Hymenoptera: Braconidae) on various host species of Lepidoptera

The objective of this study was to investigate the reproductive performance of Bracon hebetor, a larval ecto-parasitiod of stored product moth species, on several species of lepidopteran insects, including Plodia interpunctella, Ephestia kuehniella, E. cautella, Corcyra cephalonica, Amyelois transitella, and Galleria mellonella. B. hebetor females were introduced singly into experimental arenas and allowed to sting and oviposit for five days with a fresh host given daily. Experiments were conducted using Petri dishes (100 x 15 mm). In life history studies, B. hebetor females were introduced singly into Petri dishes and given a single host larva every day throughout their life time. I also investigated the effect of parasitoid and host density, and size of rearing containers on progeny production and sex ratio of B. hebetor. Statistical analyses were done using PC SAS Version 9.1. The mean cumulative fecundity in five days was highest on A. transitella (106.42 +/- 5.19) and lowest on T. bisselliella (9.64 +/- 1.28). The egg-to-adult survivorship and progeny sex ratio were also significantly affected by the host species. The highest percentage of parasitoid survival was on A. transitella (84.07 +/- 2.26) and zero on T. bisselliella. Daily fecundity was highest on G. mellonella (22.09 +/- 0.42) and C. cephalonica (21.64 +/- 0.35) and lowest on E. cautella (13.39 +/- 0.24). The egg-to-adult survivorship and progeny sex ratio were also significantly affected by the host species. The highest percentage of parasitoid survival was on A. transitella (75.69 +/- 1.99) and C. cephalonica (75.42 +/- 2.47) and lowest on G. mellonella (49.71 +/- 1.74). Although B. hebetor can paralyze and lay eggs on several moth species, it can develop and reproduce optimally on only a few species of pyralid hosts. Maximum progeny production in mass-rearing (188.89 +/- 12.28 adults) was achieved with eight female wasps on a density of 50 host larvae in glass jars of approximately 0.25 L. The possible application of these results for biological control of stored product insects is discussed.