Data accessibility
The genome assemblies are available from GenBank under the accession accession numbers CP046107 (closed genome of the symbiont from H. acanthopus ) and WNLJ00000000 (draft genome of Polyplax serratasymbiont in 39 contigs). Amplicon data for the lice microbiomes (demultiplexed, quality filtered and merged) are available at https://www.ebi.ac.uk/ena/data/view/PRJEB35541. OTU abundance tables, and accession numbers for individual samples of Polyplax serrataand Hoplopleura sp. (sequences of COI genes) are available in supplementary material.