Host deprivation effects on population performance and paralysis rates of Habrobracon hebetor (hymenoptera: Braconidae)

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 F-1 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 F-0 generation occurred after 19 days of host deprivation (PW-20 treatment). The life table parameters (intrinsic rate of increase, r; finite rate of increase, lambda; and net reproductive rate, R-0) and the paralysis rate parameters (net paralysis rate, C-0; transformation rate, Q(p); stable paralysis rate, psi; and finite paralysis rate, omega) of F-1 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.

Automated summary

The study found that host deprivation for 19 days did not decrease the effectiveness of H. hebetor. F-1 individuals after PW-20 treatment had higher life table parameters and paralysis rate parameters compared to those without host deprivation. No difference was observed between the two host deprivation treatments, indicating that immediate host deprivation may be just as effective as deprivation after 1 day of host contact.