Wolbachia reduces virus infection in a natural population

Wolbachia is a maternally transmitted bacterial symbiont that is estimated to infect approximately half of arthropod species. In the laboratory it can increase the resistance of insects to viral infection, but its effect on viruses in nature is unknown. Characterising the virome by metagenomic sequencing and testing individual flies for infection revealed virus-specific protective effect of Wolbachia in a natural population of Drosophila melanogaster. The antiviral effects of Wolbachia may contribute to its extraordinary success, and in nature the symbiont may be an important component of the antiviral defences of insects.