So far, large numbers of studies investigating the microbiome have focused on gut microbiota and less have addressed the microbiome of the skin. Especially in avian taxa our understanding of the ecology and function of these bacteria remains incomplete. The involvement of skin bacteria in intra-specific communication has recently received attention, and has highlighted the need to understand what information is potentially being encoded in bacterial communities. Using next generation sequencing techniques, we characterised the skin microbiome of wild zebra finches, aiming to understand the impact of sex, age and group composition on skin bacteria communities. For this purpose, we sampled skin swabs from both sexes and two age classes (adults and nestlings) of 12 different zebra finch families and analysed the bacterial communities. Using 16S rRNA sequencing we found no effect of age, sex and family on bacterial diversity (alpha diversity). However, when comparing the composition (beta diversity), we found that animals of social groups (families) harbour highly similar bacterial communities on their skin with respect to community composition. Within families, closely related individuals shared significantly more bacterial taxa than non-related animals. In addition, we found that age (adults vs. nestlings) affected bacterial composition. Finally, we found that spatial proximity of nest sites, and therefore individuals, correlated with the skin microbiota similarity. Birds harbour very diverse and complex bacterial assemblages on their skin. These bacterial communities are distinguishable and characteristic for intraspecific social groups. Our findings are indicative for a family-specific skin microbiome in wild zebra finches. Genetics and the (social) environment seem to be the influential factors shaping the complex bacterial communities. Bacterial communities associated with the skin have a potential to emit volatiles and therefore these communities may play a role in intraspecific social communication, e.g. via signalling social group membership.

中文翻译：

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家庭事务：皮肤微生物组反映了野生斑马雀科动物的社会群体和空间接近性

迄今为止，大量研究微生物组的研究都集中在肠道菌群上，而针对皮肤微生物组的研究则很少。尤其是在禽类中，我们对这些细菌的生态和功能的了解仍然不完整。皮肤细菌参与种内通讯的方法最近受到关注，并强调需要了解细菌群落中可能编码的信息。使用下一代测序技术，我们表征了野生斑马雀的皮肤微生物组，旨在了解性别，年龄和群体组成对皮肤细菌群落的影响。为此，我们对来自12个不同斑马雀科的两个性别和两个年龄段（成人和雏鸟）的棉签进行了采样，并分析了细菌群落。使用16S rRNA测序，我们发现年龄，性别和家庭对细菌多样性（α多样性）没有影响。但是，在比较组成（β多样性）时，我们发现，社会群体（家庭）的动物在皮肤上就群落组成而言具有高度相似的细菌群落。在家庭内部，密切相关的个体比不相关的动物共享更多的细菌分类群。此外，我们发现年龄（成人与雏鸟）会影响细菌的组成。最后，我们发现巢位以及个体的空间接近度与皮肤微生物群相似性相关。鸟类的皮肤上有多种多样且复杂的细菌。这些细菌群落是种内社会群体的独特特征。我们的发现表明野生斑马雀科中有特定于家庭的皮肤微生物组。遗传学和（社会）环境似乎是影响复杂细菌群落的影响因素。与皮肤相关的细菌群落具有散发挥发物的潜力，因此，这些群落可能在种内社会交流中发挥作用，例如，通过信号传递社会团体成员身份。