Influence of a diet containing tobacco on the biology of Ephestia kuehniella (Lepidoptera: Pyralidae) and its parasitoid Habrobracon hebetor (Hymenoptera: Braconidae)

摘要

Host diet often infl uences its biological parameters and the success of their parasitoids, both in mass rearing, fi eld research and parasitism in applied biological control programs. Habrobracon hebetor (Say, 1836) (Hymenoptera: Braconidae) is an important biological control agent of the fl our moth Ephestia kuehniella (Zeller, 1879) (Lepidoptera: Pyralidae), which infests tobacco, grain and other products in storage. This study aimed to evaluate the effect of different proportions of tobacco in artifi cial diets on the biological parameters of the host E. kuehniella and its parasitoid H. hebetor. Four classes of Virginia tobacco with different sugar and nicotine concentrations were added to fl our diets for moths in different percentages (5, 10 and 15%).The experimental design was completely randomized in a 3 × 4 factorial scheme (percentage of dietary tobacco × class of tobacco). In the parasitoid bioassays, hosts fed only with 5% tobacco were used. For E. kuehniella, the development time (egg-adult), viability of immature stages, sex ratio, fecundity, egg viability and longevity were measured. For H. hebetor, percentage parasitism, offspring sex ratio, number of paralyzed and parasitized larvae, egg-adult viability and parasitism preference were measured. Tobacco classes and percentages added to the diet infl uenced the development time and viability of E. kuehniella. The 5% host diet did not infl uence the different biological parameters and behaviour of H. hebetor. For mass rearing of H. hebetor, it is unnecessary to add tobacco to the artifi cial diet in order to improve parasitoid performance.