BACKGROUND Habrobracon hebetor (Hymenoptera: Braconidae) is a gregarious ectoparasitoid that attacks the larvae of several species of pyralid and noctuid moths. The reproduction and population dynamics of parasitoids in general are affected by host deprivation. However, how host deprivation affects H. hebetor is unknown. The effect of host deprivation on the parental generation, life table parameters, and the paralysis rate of the F1 generation of H. hebetor were evaluated using the age‐stage, two‐sex life table under laboratory conditions. RESULTS The results indicated that the greatest longevity and the least lifetime fecundity of the F0 generation occurred after 19 days of host deprivation (PW‐20 treatment). The life table parameters (intrinsic rate of increase, r; finite rate of increase, λ; and net reproductive rate, R0) and the paralysis rate parameters (net paralysis rate, C0; transformation rate, Qp; stable paralysis rate, ψ; and finite paralysis rate, ω) of F1 individuals after PW‐20 treatment were significantly higher than those of individuals subjected to the control treatment (no host deprivation). However, no difference was detected between the two host deprivation treatments: host deprivation after 1 day of host contact and immediate host deprivation (PW treatment). CONCLUSION Our results demonstrated that the effectiveness of H. hebetor did not decrease even during host deprivation for 19 days. Meanwhile, it was observed that mass rearing of the parasitoid could be improved by providing 10 individuals of 5th instar larvae of Ephestia elutella (Lepidoptera: Pyralidae) with a 20% honey‐water solution. © 2020 Society of Chemical Industry

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Habrobracon hebetor (Say) is an important biological control agent for lepidopteran pests of stored products. In this study, the age-specific functional response, paralysis rate, and parasitism rate of H. hebetor under different host deprivation treatments (PC: without host deprivation, used as the control, P1d: host deprivation, but the host was removed after 1 d contact, and PW: host deprivation from beginning) were evaluated at different larval densities (5, 10, 20, 40, and 80) of the Ephestia elutella (Hübner) at 28 ± 1°C, 75 ± 5% RH and 16:8 h L:D. Ages of parasitoid females used were 2, 5, 10, and 20 d old. The logistic regression results indicated that the functional response of H. hebetor females under different host deprivation treatments was type II. The longest handling time was observed in 20-d old females, while the shortest handling time and highest maximum attack rate (T/Th) were estimated at the age of 2 d in all treatments. The paralysis and parasitism rates of H. hebetor were the highest at 2, 5, and 10-d old in all treatments. The results of this study suggest that H. hebetor females up to 10-d old can be used as an efficient biological control agent against E. elutella. The data of this study can also be used to predict the efficacy of different aged H. hebetor females in controlling E. elutella populations.

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Intraguild predation interactions have substantial theoretical and practical implications for the dynamics of natural competitor populations used for biological control. Intraguild predation on parasitized aphids not only has a direct, negative effect on the parasitoid species, but it may indirectly influence the predator’s development, survival, reproduction and predation rates. In this study, we used two-sex life table theory, life table parameters and predation rates of Aphidoletes aphidimyza (Rondani) to compare when its populations fed on aphids (Myzus persicae Sulzer) (Hemiptera: Aphididae) that were either unparasitized or parasitized by Aphidius gifuensis (Ashmead) (Hymenoptera: Braconidae). Our results showed that individuals of A. aphidimyza were capable of completing their development and attaining maturity when they fed on parasitized aphids. Although feeding on parasitized aphids did not influence the survival rates of immature A. aphidimyza, it did significantly slow their development and extended their longevity, thereby reducing the fecundity and predation rates of A. aphidimyza. These findings may be pivotal for better understanding the sustained coexistence of predators with parasitoids in the biological control of aphids.