Figure 2.

Gut microbiomes reflect social group membership and grooming duration. (a) Genetic relatedness predicts Bray–Curtis dissimilarity in gut microbiome composition for pairs of sifaka belonging to different social groups (circles) but not for pairs belonging to the same social group (triangles). Although related individuals in different groups share microbiota, kinship is not driving the compositional homogeneity observed among group members. (b) Social network based on grooming interactions in the year prior to and including microbiome sampling among four sifaka social groups (II, III, IV, V) inhabiting Kirindy Mitea National Park. Nodes (N = 33) represent individuals. Lines represent grooming interactions between individuals, and thicker lines reflect stronger grooming relationships. (c) Social distance in the grooming network predicts Bray–Curtis dissimilarity on a global (network) level (black line) but not for pairs belonging to the same or different social groups (triangles and circles, respectively). Thus, patterns of microbial similarity reflect social divisions among sifaka groups. (Online version in colour.)