Escallón C, Belden L K, Moore I T
Department of Biological Sciences, Virginia Tech, Blacksburg, VA 24061, USA.
Departamento de Ciencias Básicas, Universidad de La Salle, Cra 2 No. 10-70, Bogotá, Colombia.
Integr Org Biol. 2019 Jan 9;1(1):oby009. doi: 10.1093/iob/oby009. eCollection 2019.
The symbiotic microbial communities, or "microbiomes," that reside on animals are dynamic, and can be affected by the behavior and physiology of the host. These communities provide many critical beneficial functions for their hosts, but they can also include potential pathogens. In birds, bacteria residing in the cloaca form a complex community, including both gut and sexually-transmitted bacteria. Transmission of cloacal bacteria among individuals is likely during the breeding season, when there is direct cloacal contact between individuals. In addition, the major energetic investment in reproduction can draw resources away from immune responses that might otherwise prevent the successful establishment of microbes. We assessed dynamic variation in the cloacal microbiome of free-living rufous-collared sparrows () through sequential breeding and non-breeding seasons. We found that the cloacal bacterial communities differed between the sexes when they were in breeding condition. Further, in males, but not in females, the bacterial community became more diverse with the onset of reproduction, and then decreased in diversity as males transitioned to non-breeding condition. Individuals sampled across sequential breeding seasons did not accumulate more bacterial taxa over seasons, but bacterial community composition did change. Our results suggest that the cloacal microbiome in birds is dynamic and, especially in males, responsive to breeding condition.
寄居于动物身上的共生微生物群落，即“微生物组”，是动态变化的，并且会受到宿主行为和生理状态的影响。这些群落为宿主提供许多关键的有益功能，但其中也可能包括潜在病原体。在鸟类中，泄殖腔中的细菌形成一个复杂的群落，包括肠道细菌和性传播细菌。在繁殖季节，当个体之间存在直接的泄殖腔接触时，泄殖腔细菌在个体间传播的可能性很大。此外，繁殖过程中的主要能量投入可能会使原本可用于免疫反应的资源被挪用，而免疫反应原本可能会阻止微生物的成功定植。我们通过连续的繁殖季节和非繁殖季节，评估了自由生活的棕颈雀鹀（）泄殖腔微生物组的动态变化。我们发现，处于繁殖状态时，两性的泄殖腔细菌群落存在差异。此外，在雄性中（而非雌性中），随着繁殖的开始，细菌群落变得更加多样化，然后随着雄性转变为非繁殖状态，其多样性降低。在连续繁殖季节采样的个体并没有随着季节的推移积累更多的细菌分类群，但细菌群落组成确实发生了变化。我们的结果表明，鸟类的泄殖腔微生物组是动态的，尤其是在雄性中，对繁殖状态有反应。
