(a) Topology showing evolutionary relationships of the three Sodalis lineages identified in this study (SAL1, SAL2, SLEU), three previously sequenced Sodalis genomes (So. praecaptivus, So. glossinidius, So. pierantonius), and several free-living (host: ‘none’) taxa as out-groups. Bolded taxa are symbionts of insects. Boxplots show genome-wide distributions of dN/dS values. dN/dS ratios of Sodalis symbionts were compared to So. praecaptivus using Wilcoxon rank-sum tests and significant differences are shown with asterisks. (b) Proportions of reads originating from the two Sodalis lineages SAL1 and SAL2 in shotgun sequencing data for 36 L. albipes specimens. Samples are separated by populations of origin shown by maps.