A comparative analysis of -induced host reproductive phenotypes reveals transition rate heterogeneity.

The endosymbiotic bacterium infects a wide range of arthropods and their relatives. It is an intracellular parasite transmitted through the egg from mother to offspring. can spread and persist through various means of host reproductive manipulation. How these different mechanisms of host manipulation evolved in is unclear. Which host reproductive phenotype is most likely to be ancestral and whether evolutionary transitions between some host phenotypes are more common than others remain unanswered questions. Recent studies have revealed multiple cases where the same strain can induce different reproductive phenotypes in different hosts, raising the question to what degree the induced host phenotype should be regarded as a trait of . In this study, we constructed a phylogenetic tree of and analyzed the patterns of host phenotypes along that tree. We were able to detect a phylogenetic signal of host phenotypes on the tree, indicating that the induced host phenotype can be regarded as a trait. However, we found no clear support for the previously stated hypothesis that cytoplasmic incompatibility is ancestral to in arthropods. Our analysis provides evidence for heterogeneous transition rates between host phenotypes.