Co-habiting ants and silverfish display a converging feeding ecology

We studied how host specialization in animals might be associated with changes in the bacterial microbiome. We sampled a collection of silverfish species that display divergent myrmecophilous lifestyles. Specifically, we focused on Messor-specialized, Aphaenogaster-specialized, obligate generalist, facultative generalist, and unassociated silverfish of the Lepismatidae and the Nicoletiidae family. In parallel, we also sampled the respective ant hosts. We amplified a fragment of the COI, V4 16S rRNA, and V1-V2 16S rRNA and sequenced the amplicons using an Illumina NovaSeq instrument. We observed that silverfish lifestyle shapes the density and composition of the bacterial microbiome. Messor-specialization was associated with a higher microbiome density and a higher proportion of heterofermentative Lactobacillaceae. Moreover, the ant nest explained the infection profile of Weissella bacteria in silverfish and ant workers. Together, this shows that co-habitation and host specialization are important determinants for the bacterial microbiome in arthropods.