Contrasting effects of Wolbachia on cytoplasmic incompatibility and fecundity in the haplodiploid mite Tetranychus urticae

Recent studies on Wolbachia-induced incompatibility in haplodiploid insects and mites have revealed a diversity of cytoplasmic incompatibility (CI) patterns among host species. Here, we report intraspecific diversity in CI expression among four strains of the arrhenotokous mite Tetranychus urticae and in T. turkestani. Variability of CI expression within T. urticae ranged from no CI to complete CI, and included either female embryonic mortality or male conversion types of CI. A fecundity cost attributed to the infection with the high-CI Wolbachia strain was the highest ever recorded for Wolbachia (-80 to -100% decrease). Sequence polymorphism at a 550-bp-portion of Wolbachia wsp gene revealed two clusters distant by 21%, one of which included three Wolbachia strains infecting mite populations sampled from the same host-plant species, but showing distinct CI patterns. These data are discussed in the light of theoretical predictions on the evolutionary pathways followed in this symbiotic interaction.