Unveiled feather microcosm: feather microbiota of passerine birds is closely associated with host species identity and bacteriocin-producing bacteria

Abstract

The functional relevance of microbiota is a key aspect for understanding host-microbiota interactions. Mammalian skin harbours a complex consortium of beneficial microorganisms known to provide health and immune-boosting advantages. As yet, however, little is known about functional microbial communities on avian feathers, including their co-evolution with the host and factors determining feather microbiota (FM) diversity. Using 16S rRNA profiling, we investigated how host species identity, phylogeny and geographic origin determine FM in free-living passerine birds. Moreover, we estimated the relative abundance of bacteriocin-producing bacteria (BPB) and keratinolytic feather damaging bacteria (FDB) and evaluated the ability of BPB to affect FM diversity and relative abundance of FDB. Host species identity was associated with feather bacterial communities more strongly than host geographic origin. FM functional properties differed in terms of estimated BPB and FDB relative abundance, with both showing interspecific variation. FM diversity was negatively associated with BPB relative abundance across species, whereas BPB and FDB relative abundance was positively correlated. This study provides the first thorough evaluation of antimicrobial peptides-producing bacterial communities inhabiting the feather integument, including their likely potential to mediate niche-competition and to be associated with functional species-specific feather microbiota in avian hosts.

Fig. 1

Barplots showing relative abundance of 16S rRNA reads for the (a) dominant bacterial phyla and (b) classes in particular feather microbiota samples (ID) and host passerine species (AA = Acrocepalus arundinaceus, LL = Locustella luscinioides, SE = Sitta europaea, PA = Periparus ater, FA = Ficedula albicollis, PP = Phoenicurus phoenicurus, RR = Riparia riparia)

Fig. 2

Boxplots of (a) Shannon diversities, (b) BPB relative abundance and (c) keratinolytic FDB relative abundance within the feather microbiota of particular passerine host species (AA = Acrocepalus arundinaceus, LL = Locustella luscinioides, SE = Sitta europaea, PA = Periparus ater, FA = Ficedula albicollis, PP = Phoenicurus phoenicurus, RR = Riparia riparia). (Illustrations by Jan Hošek)

Fig. 3

Non-metric Multidimensional Scaling for among-sample divergence in composition (β—diversity) of feather microbial community profiles based on (a) Bray-Curtis, (b) Jaccard, (c) weighted UniFrac and (d) unweighted UniFrac dissimilarities. Different colours denote host species identity

Fig. 4

Heatmap denoting abundance of the dominant bacterial OTUs detected in the feather microbiota of individual passerine host species. Both rows and columns are clustered using the Ward algorithm. Identity of host species is indicated by column annotation, whereas row annotations correspond to the taxonomic assignation to the bacterial phyla

Fig. 5

Procrustean superimposition for PCoA‐scaled phylogenetic vs. feather microbiota distance. Feather microbiota divergence was calculated using (a) Bray-Curtis, (b) Jaccard, (c) unweighted UniFrac and (d) weighted UniFrac dissimilarities. Different colours denote host species identity

Fig. 6

Euler diagram for the relative abundance of bacteriocin-producing (BPB) and keratinolytic (FDB) OTUs within all observed OTUs in the feather microbiota of passerine host species. Numbers in the diagram denote the proportion (%) of unique and shared OTUs

Fig. 7

Correlation between (a) BPB relative abundance and Shannon diversity and (b) relative abundance of BPB and keratinolytic FDB within the feather microbiota of host passerine species. Different colours denote host species identity