1 Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California , Davis, CA , USA.
2 Department of Entomology and Nematology, University of California , Davis, CA , USA.
Proc Biol Sci. 2019 Mar 13;286(1898):20182295. doi: 10.1098/rspb.2018.2295.
Human provisioning can shape resource availability for wildlife, but consequences for microbiota availability and exchange remain relatively unexplored. Here, we characterized microbial communities on bills and faecal material of hummingbirds and their food resources, including feeders and floral nectar. We experimentally manipulated bird visitation to feeders and examined effects on sucrose solution microbial communities. Birds, feeders and flowers hosted distinct bacterial and fungal communities. Proteobacteria comprised over 80% of nectar bacteria but feeder solutions contained a high relative abundance of Proteobacteria, Firmicutes and Actinobacteria. Hummingbirds hosted bacterial taxa commonly found in other birds and novel genera including Zymobacter [Proteobacteria] and Ascomycete fungi. For feeders, bird-visited and unvisited solutions both accumulated abundant microbial populations that changed solution pH, but microbial composition was largely determined by visitation treatment. Our results reveal that feeders host abundant microbial populations, including some bird-associated microbial taxa. Microbial taxa in feeders were primarily non-pathogenic bacteria and fungi but differed substantially from those in floral nectar. These results demonstrate that human provisioning influences microbial intake by free-ranging hummingbirds; however, it is unknown how these changes impact hummingbird gastrointestinal flora or health.
人类的供养可以塑造野生动物的资源可利用性，但对于微生物的可利用性和交换的后果仍然相对未知。在这里，我们描述了蜂鸟的喙和粪便材料以及它们的食物资源（包括喂食器和花蜜）上的微生物群落。我们通过实验操纵蜂鸟对喂食器的访问，并研究了其对蔗糖溶液微生物群落的影响。鸟类、喂食器和花朵上都存在独特的细菌和真菌群落。变形菌门（Proteobacteria）构成了花蜜细菌的 80%以上，但喂食器溶液中含有大量的变形菌门、厚壁菌门（Firmicutes）和放线菌门（Actinobacteria）。蜂鸟还携带了其他鸟类常见的细菌分类群和新型属，包括动胶菌属（Zymobacter）[变形菌门]和子囊菌门真菌。对于喂食器，鸟类访问和未访问的溶液都积累了丰富的微生物种群，这些种群改变了溶液的 pH 值，但微生物组成主要取决于访问处理。我们的结果表明，喂食器中存在丰富的微生物种群，包括一些与鸟类相关的微生物分类群。喂食器中的微生物分类群主要是非致病性细菌和真菌，但与花蜜中的微生物有很大的不同。这些结果表明，人类的供养会影响自由放养的蜂鸟摄入微生物；然而，这些变化如何影响蜂鸟的胃肠道菌群或健康状况尚不清楚。
