Evidence of cuticular hydrocarbon profile alterations by Wolbachia in females, but not males, of an aculeate parasitoid wasp

The effects of the maternally-inherited intracellular bacteria of the genus Wolbachia on insect physiology remain obscure for many hosts. Here, we report a link between the infection of Wolbachia of supergroup A and the cuticular hydrocarbon (CHC) profile in the parasitoid wasp Myrmilla capitata (Lucas) (Hymenoptera: Mutillidae), providing the second evidence in insects for such phenomenon. By comparing infected and uninfected individuals of M. capitata sampled at a nest aggregation of its host (the eusocial bee Lasioglossum malachurum (Kirby) (Hymenoptera: Halictidae)), we discovered that Wolbachia-infected wasp females, but not males, have a lower number of CHC compounds and a higher abundance of long-chain compounds, compared with uninfected females. Infected females also showed a lower inter-individual variation in CHC profile, suggesting that Wolbachia produces a uniform physiological alteration. Both infected and uninfected wasps greatly differed from hosts, which overall presented a less complex CHC profile, excluding that the symbiont increases the reproductive success of M. capitata by conferring to it a chemical mimicry or chemical insignificance. One of the most promising hypothesis raised by our results is that Wolbachia may alter wasp sexual communication, perhaps in a way that increases the attraction of males towards infected females, consequently reducing zygotic lethality due to cytoplasmic incompatibility.