Russell, J.A.

The ants (Hymenoptera: Formicidae) are unique and enigmatic hosts of prevalent Wolbachia (Alphaproteobacteria) symbionts

Intracellular bacteria from the genus Wolbachia are the most prevalent microbes found among the arthropods, shaping the ecology and evolution of their hosts through selfish and mutualistic means. The ants comprise an interesting group of Wolbachia hosts given their status as eusocial haplodiploids with commonly biased sex ratios. Although experimental hurdles have obscured Wolbachia's impacts on the ants, published findings have still managed to document unique aspects of ant-Wolbachia interactions, including exceptional levels of multiple infection, symbiont curing, and potential effects of host mobility on the spread and evolution of these heritable symbionts. To further develop hypotheses on the significance of Wolbachia and the forces that shape their distributions across the ants and beyond, I synthesize the results of a growing body of literature that has largely focused on symbiont prevalence. Results from surveys across ~ 455 species indicate that ants are common hosts, although infection levels differ among ant genera and likely across taxa with different modes of colony founding. A meta-analysis of Wolbachia distributions across ~ 2,600 other arthropod species revealed a similar pattern of variation among lower-level taxa, suggesting that the ecological and evolutionary shifts governing infection dynamics have occurred on recent timescales. Phylogenetic analyses suggest that ant-associated Wolbachia symbionts show some degree of host specificity. However, related strains are generally distributed across ants from multiple tribes and genera, while ants from different locations harbor strains from distinct lineages on the Wolbachia phylogeny. Combined, the trends and attributes of these symbioses reveal potential causes of Wolbachia proliferation, while hinting at the impacts of enigmatic microbial symbionts across this diverse group of hymenopterans.

Open access, licensed under CC BY 4.0. © 2012 The Author(s).

Symbiosis, colony founding, reproductive manipulation, coevolution, review.