Lack of impact of Wolbachia on foraging behavior and morphological characteristics of the parasitoid wasp, Habrobracon hebetor (Braconidae)

Abstract

Wolbachia are the most widespread intracellular alphaproteobacteria in insects with a variety of phenoptypic effects on the fitness and reproduction of their host, but much less is known about how these bacteria affect host behavior. In this study, we asked whether Wolbachia affects the foraging behavior of the parasitoid wasp Habrobracon hebetor (Hym.: Braconidae), an important biological control agent of many lepidopteran larvae. To test this, we analyzed the functional and numerical responses of Wolbachia-infected and uninfected (tetracycline cured) wasps, as well as morphological parameters. Functional response analysis showed Holling type II responses in both the Wolbachia-infected and uninfected females. The handling time and searching efficiency of Wolbachia-infected and uninfected females were similar, although the estimated maximum parasitism rate was shorter in infected females. Regardless of Wolbachia infection status, there was a negative non-linear relationship between the number of larvae parasitized by a female and an increase in the host density, reflecting a decrease in the total number of eggs laid. Our results also showed that Wolbachia had no effect on morphological traits of the parasitoid wasp. Together, these results suggest that Wolbachia which are prevalent in H. hebetor have limited impact on foraging behavior and morphology.