Identifying the Role of Elevation, Geography, and Species Identity in Structuring Turtle Ant (Cephalotes Latreille, 1802) Bacterial Communities.

ABSTRACT

Bacterial communities in animals are often necessary for hosts to survive, particularly for hosts with nutrient-limited diets. The composition, abundance, and richness of these bacterial communities may be shaped by host identity and external ecological factors. The turtle ants (genus Cephalotes) are predominantly herbivorous and known to rely on bacterial communities to enrich their diet. Cephalotes have a broad Neotropical distribution, with high diversity in the South American Cerrado, a geologically and biologically diverse savanna. Using 16S rRNA amplicon sequencing, we examined the bacterial communities of forty-one Cephalotes samples of sixteen different species collected from multiple locations across two sites in the Cerrado (MG, Brazil) and compared the bacterial communities according to elevation, locality, species, and species group, defined by host phylogeny. Beta diversity of bacterial communities differed with respect to all categories but particularly strongly when compared by geographic location, species, and species group. Differences seen in species and species groups can be partially explained by the high abundance of Mesorhizobium in Cephalotes pusillus and Cephalotes depressus species groups, when compared to other clades via the Analysis of Composition of Microbiome (ANCOM). Though the Cephalotes bacterial community is highly conserved, results from this study indicate that multiple external factors can affect and change bacterial community composition and abundance.