Data from: Chemical regulation of body feather microbiota in a wild bird

The microbiota has a broad range of impacts on host physiology and behaviour, pointing out the need to improve our comprehension of the drivers of host microbiota composition. Of particular interest is whether the microbiota is acquired passively, or whether and to what extent hosts themselves shape the acquisition and maintenance of their microbiota. In birds, the uropygial gland produces oily secretions used to coat feathers that have been suggested to act as an antimicrobial defence mechanism regulating body feather microbiota. However, our comprehension of this process is still limited. In this study, we for the first time coupled high-throughput sequencing of the microbiota of both body feathers and the direct environment (i.e. the nest) in great tits with chemical analyses of the composition of uropygial gland secretions to examine whether host chemicals have either specific effects on some bacteria or non-specific broad-spectrum effects on the body feather microbiota. Using a network approach investigating the patterns of co-occurrence or co-exclusions between chemicals and bacteria within the body feather microbiota, we found no evidence for specific pro or anti-microbial effects of uropygial gland chemicals. However, we found that one group of chemicals was negatively correlated to bacterial richness on body feathers, and a higher production of these chemicals was associated with a poorer body feather bacterial richness compared to the nest microbiota. Our study provides evidence that chemicals produced by the host might function as a non-specific broad-spectrum antimicrobial defence mechanism limiting colonization and/or maintenance of bacteria on body feathers, providing new insight about the divers of the host’s microbiota composition in wild organisms.

微生物群（microbiota）对宿主生理与行为具有广泛影响，这凸显出深化对宿主微生物群组成驱动因素认知的必要性。尤为值得关注的核心问题是：微生物群是否通过被动方式获得，抑或是宿主自身是否参与塑造其微生物群的获取与维持过程，以及该过程的影响程度如何。在鸟类中，尾脂腺（uropygial gland）可分泌油性分泌物用于梳理羽毛，此前已有研究提出，该分泌物可作为抗菌防御机制，对体羽微生物群发挥调控作用。然而，目前学界对这一过程的认知仍较为有限。本研究首次将大山雀体羽及其直接生存环境（即巢穴）的微生物群高通量测序（high-throughput sequencing）结果，与尾脂腺分泌物组成的化学分析相结合，以探究宿主分泌的化学物质对体羽微生物群究竟存在特异性抗菌效应，还是非特异性广谱抗菌效应。本研究采用网络分析法，对体羽微生物群内化学物质与细菌之间的共现或互斥模式进行分析，未发现尾脂腺分泌物具有特异性促菌或抑菌效应的相关证据。但研究结果显示，某一类化学物质与体羽的细菌丰富度呈负相关；相较于巢内微生物群，此类化学物质分泌量更高的个体，其体羽细菌丰富度显著更低。本研究证实，宿主分泌的化学物质可作为非特异性广谱抗菌防御机制，限制细菌在体羽上的定殖与/或维持，为野生生物宿主微生物群组成的驱动因素研究提供了全新视角。