Asymmetric sex body size and reproductive fitness relation and offspring population parameters of Habrobracon hebetor (Say) (Hymenoptera: Braconidae)

Abstract

Parasitoids show a strong relationship between body size and fitness, but it is unclear whether the relationship is asymmetric or symmetric in males and females of Habrobracon hebetor (Say) (Hymenoptera: Braconidae). This study investigated the effects of male and female body sizes on the reproductive fitness (e.g., longevity and fecundity) of the F0 generation and the population fitness (e.g., survival rate, body size, longevity, and fecundity) of the F1 generation at 28 ± 1 °C, 75 ± 5% relative humidity and 16:8 h light:dark period based on the age-stage two-sex life table theory. The results showed that the body size of F0 generation males and females significantly affected their reproductive fitness, but not the body size of the F1 generation. Larger females had longer lifetimes and oviposition days, and higher reproductive rates than smaller females. Moreover, only small ♀ × small ♂, but not large ♀ × small ♂, small ♀ × large ♂, and large ♀ × large ♂, had a significant impact on the life history parameters, population parameters, paralysis rate, and parasitism rate of the F1 offspring population. Interestingly, the population size, paralysis rate, and variability of the F1 offspring with different body sizes increased to a stable status after 50 days. The study also found that the Weibull function could not fit the survival rate of the parasitoid wasp well. These findings deepen our understanding of the ecology of H. hebetor population and provide important technical parameters for mass-rearing and application of these parasitoid wasps.