Influence of Parthenogenesis-Inducing Wolbachia Infection and Sexual Mode on Trichogramma kaykai (Hymenoptera: Trichogrammatidae) Fitness

摘要

Wolbachia pipientis represents one of the most pervasive bacterial infections in the world, with estimates of over one million arthropods species infected. Parthenogenesis-inducing (PI) Wolbachia in various haplodiploid species effectively feminizes male offspring through a process called gamete duplication and converts the reproductive mode of infected females from arrhenotoky (fertilized eggs undergo female development, unfertilized eggs undergo male development) to thelytoky (fertilized and unfertilized eggs undergo female development). The fitness consequences associated with PI Wolbachia infection are of particular interest to ecologists and evolutionary biologists given the extreme effect that infection has on the reproductive mode of infected individuals. We use a model PI Wolbachia infected species, Trichogramma kaykai Pinto (Hymenoptera: Trichogrammatidae), to investigate the effects of infection status and mating status on T. kaykai fitness. Three genotypically distinct isofemale cultures were used to test whether fitness (number of offspring reaching pupal stage, number of female offspring, and pupal survival) differed among infected unmated, infected mated, and antibiotically cured mated females. Significant survival costs were observed for mated Wolbachia-infected females, and fecundity costs were observed for mated and unmated Wolbachia-infected females, with significant variation for these costs across host genotypes.