Abstract
Wolbachia pipientis is an alpha-proteobacterial, obligate intracellular microbe and arguably the most successful infection on our planet, colonizing 40-60% of insect species. Wolbachia are also present in most, but not all, filarial nematodes where they are obligate mutualists and are the targets for anti-filarial drug discovery. Although Wolbachia are related to important human pathogens they do not infect mammals, but instead are well known for their reproductive manipulations of insect populations, inducing the following phenotypes: male-killing, feminization, parthenogenesis induction, or cytoplasmic incompatibility (CI). The most common of these, CI, results in a sperm-egg incompatibility and increases the relative fecundity of infected females in a population. In the last decade, Wolbachia have also been shown to provide a benefit to insects, where the infection can inhibit RNA virus replication within the host. Wolbachia cannot be cultivated outside of host cells and no genetic tools are available in the symbiont, limiting approaches available to its study. This means that many questions fundamental to our understanding of Wolbachia basic biology remained unknown for decades. The tenth biennial international Wolbachia conference, "Wolbachia Evolution, Ecology, Genomics and Cell Biology: A Chronicle of the Most Ubiquitous Symbiont", was held on June 17-22, 2018, Salem, MA USA. In the review below we highlight the new science presented at the meeting, link it to prior efforts to answer these questions across the Wolbachia genus, and the importance to the field of symbiosis. The topics covered in this review are based on the presentations at the conference.