Polyandry and host-endosymbiont conflicts in spider mites : Présentation travaux

Abstract :

In spider mites, only the first mating of a female is effective. Still, males often copulate with mated females. This behaviour may be adaptive if it decreases the costs of incompatible crosses that occur, for example, when uninfected females mate with males infected by Wolbachia, an endosymbiotic bacteria. Such crosses result into cytoplasmic incompatibility (CI), entailing the embryonic death of fertilized offspring. Wolbachia-uninfected females are thus expected to evolve strategies to avoid the costs of CI. For example, they may mate multiply to recover offspring viability. However, such recovery may not be effective in species with first male precedence and its occurrence may be contingent upon infection history.To test this, we performed experimental evolution of spider-mite populations that were infected or uninfected by Wolbachia (controls), or in which Wolbachia-uninfected females were given the choice between Wolbachia-infected and Wolbachia-uninfected males at each generation (selection treatment).After 20 generations, Wolbachia-uninfected females from the selected treatment reduced the degree of CI by mating with an uninfected male after mating with an infected male. This was not the case when Wolbachia-uninfected individuals were from control populations. Our results suggest that the evolution of CI-reducing strategies is contingent upon the evolutionary history of infection.