Fig 1.
Mean relative abundance of bacterial phyla present in the cloacae of sampled adult tree swallows.
Each column depicts the phyla represented within the cloaca of an individual bird. ‘F’ and ‘M’ refer to individually sampled females and males, respectively. ‘Female Mean’ and ‘Male Mean’ depict the average phyla represented per sex. ‘All Mean’ depicts the average phyla represented across sexes.
Fig 2.
Heatmap of relative abundances (log-transformed) of the most abundant OTUs present in the cloacae of adult tree swallows.
Each column depicts individual birds sampled. ‘F’ and ‘M’ refer to individually sampled females and males, respectively. The dark green bar at the top highlights sampled females, while the light green bar highlights sampled males. Each row depicts a bacterial taxon present at a relative abundance greater than 5% in the sampled population. Bacterial taxa are labeled to the lowest possible level of taxonomic classification.
Fig 3.
Alpha diversity metrics for bacterial OTUs sampled from the cloacae of adult tree swallows.
(A) OTU richness (i.e., observed OTUs), (B), Shannon Index, and (C) Faith’s phylogenetic diversity indices were calculated. The circles represent individuals sampled of each sex.
Fig 4.
Cloacal bacterial community structure of adult tree swallows.
Non-metric multidimensional scaling (NMDS) ordinations are based on (A) Bray-Curtis and (B) Jaccard distance metrics. Each symbol represents one individual (black diamonds = females, open circles = males). Pair-bonded social partners are connected by a blue line. Points closer together exhibit individuals with more similar cloacal bacterial community structure.
Fig 5.
OTU relative abundance differences for randomized (dark gray) and sampled (white) female-male pairs. Samples on the left side of the distribution are more similar, while samples on the right side are less similar and thus exhibit greater differences.
Fig 6.
Hierarchical cluster analysis (based on Bray-Curtis dissimilarity) showing the overall level of similarity of cloacal bacterial communities for sampled females and males.
The cluster analysis using the Jaccard distance metric was visually indistinguishable from the Bray-Curtis based analysis, so we only show the latter here. ‘F’ = female, ‘M’ = male, similar color = social pair, black = individual was sampled but not its social partner.