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，凸显了深化我们对宿主微生物群组成驱动因素认知的必要性。尤为值得关注的问题在于：微生物群是被动获得的，还是宿主自身能够塑造其微生物群的获取与维持过程，以及这种塑造的程度如何。在鸟类中，尾脂腺（uropygial gland）会分泌油性分泌物以梳理羽毛，此前该分泌物被认为是一种可调控体羽微生物群的抗菌防御机制。然而，我们对这一过程的认知仍较为有限。本研究首次将大山雀（great tits）体羽及其直接生存环境（即鸟巢）的微生物群高通量测序（high-throughput sequencing），与尾脂腺分泌物组成的化学分析相结合，旨在探究宿主分泌的化学物质究竟是对特定细菌产生特异性作用，还是对体羽微生物群发挥非特异性广谱效应。通过采用网络分析法探究体羽微生物群内化学物质与细菌间的共现或互斥模式，研究团队未发现尾脂腺分泌物存在特异性促菌或抗菌效应的相关证据。但研究发现，某一类化学物质与体羽细菌丰富度呈负相关；且相较于鸟巢微生物群，这类分泌物的分泌量越高，体羽的细菌丰富度越低。本研究证实，宿主分泌的化学物质或可作为非特异性广谱抗菌防御机制，抑制体羽表面细菌的定殖与/或维持过程，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。