Comparison host population structure to microbial community patterns
Genetic structure from sponge hosts (Fig 3A) was contrasted to the microbial community dataset of S. diversicolor from a subset of the same lakes, collected by Ferreira et al 2020 (Supplemental Figure 8). The microbial community did not appear to cluster between lineages (Lineage A versus Lineage B), not between subclades within lineage B. As for geographic regions, a clear distinction of broad geographic regions (Berau versus Raja Ampat, >1,400km) could be observed in microbial community patterns, concordant to sponge host patterns. However, no clear clustering was seen for microbial communities on smaller spatial scales (<250km). Mantel tests indicated no significant correlation between host genetic distances (FST) and microbial community dissimilarities based on genus abundance (Mantel r = 0.15, p = 0.37) or on OTUs (r = 0.01,p = 0.46) (Figure 4D).