Suitability of Different Lepidopteran Host Species for Development ofBracon hebetor(Hymenoptera: Braconidae)

Abstract

Bracon hebetor Say (Hymenoptera: Braconidae) is a gregarious larval ectoparasitoid of several species of Lepidoptera that are associated with stored products. The suitability of 12 potential lepidopteran host species representing four families was studied in this study for the development and reproduction of B. hebetor. The Lepidoptera species used were the Indianmeal moth, Plodia interpunctella (Hübner), Mediterranean flour moth, Ephestia kuehniella (Zeller), almond moth, E. cautella (Walker), rice moth, Corcyra cephalonica (Walker), navel orangeworm, Amyelois transitella (Stainton), greater wax moth (laboratory reared and commercial), Galleria mellonella (Linnaeus) (all Pyralidae); tobacco budworm, Heliothis virescens (Fabricus), corn earworm, Helicoverpa zea (Boddie), beet armyworm, Spodoptera exigua (Hübner) (all Noctuidae); webbing clothes moth, Tineola bisselliella (Hummel) (Tineidae); and Angoumois grain moth, Sitotroga cerealella (Olivier) (Gelichiidae). Experiments were conducted using petri dishes (100 by 15 mm) as experimental arenas at 29 +/- 1 degrees C, 65 +/- 5% RH, and a photoperiod of 14:10 (L: D) h. B. hebetor females were introduced singly into arenas and given a full-grown host larva every day for 5 consecutive d. Paralysis of the host larvae and oviposition by B. hebetor females were significantly affected by host species. The cumulative fecundity in the 5-d period 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 to the adult stage was on A. transitella (84.07 +/- 2.26) and zero on T. bisselliella. Egg to adult development time was shortest on E. cautella (9.75 +/- 0.25 d) and longest on G. mellonella (12.63 +/- 0.28 d). Results from these studies suggest that B. hebetor females can use a wide range of lepidopteran hosts for paralysis and oviposition. However, B. hebetor cannot necessarily develop and reproduce on all host species that it can paralyze and oviposit on, and optimum reproduction is with the stored-product pyralid hosts.