Wolbachia endosymbiont responsible for cytoplasmic incompatibility in a terrestrial crustacean: effects in natural and foreign hosts

Wolbachia bacteria are vertically transmitted endosymbionts that disturb th e reproduction of many arthropods thereby enhancing their spread in host po pulations. Wolbachia are often responsible for changes of sex ratios in ter restrial isopods, a result of the feminization of genotypic males. Here we found that the Wolbachia hosted by Cylisticus convexus (wCc) caused unidire ctional cytoplasmic incompatibility (CI), an effect commonly found in insec ts. To understand the diversity of Wolbachia-induced effects in isopods, wC c were experimentally transferred in a novel isopod host, Armadillidium vul gare. wCc conserved the ability to induce CI. However, Wolbachia were not t ransmitted to the eggs, so the capacity to restore the compatibility in cro sses involving two transinfected individuals was lost. The feminizing Wolba chia hosted by A. vulgare was unable to rescue CI induced by wCc. These res ults showed that Wolbachia in isopods did not evolved broadly to induce fem inization, and that CI and the feminizing effect are probably due to differ ent mechanisms. In addition, wCc reduces the mating capacity of infected C. convexus males, suggesting that the bacteria might alter reproductive beha viour. The maintenance of wCc in host populations is discussed.