Department of Biological Sciences, Virginia Tech, Blacksburg, Virginia, United States of America.
PLoS One. 2020 Feb 11;15(2):e0228982. doi: 10.1371/journal.pone.0228982. eCollection 2020.
Host-associated microbial communities can influence the overall health of their animal hosts, and many factors, including behavior and physiology, can impact the formation of these complex communities. Bacteria within these communities can be transmitted socially between individuals via indirect (e.g., shared environments) or direct (e.g., physical contact) pathways. Limited research has been done to investigate how social interactions that occur in the context of mating shape host-associated microbial communities. To gain a better understanding of these interactions and, more specifically, to assess how mating behavior shapes an animal's microbiome, we studied the cloacal bacterial communities of a socially monogamous yet genetically polygynous songbird, the North American tree swallow (Tachycineta bicolor). We address two questions: (1) do the cloacal bacterial communities differ between female and male tree swallows within a population? and (2) do pair-bonded social partners exhibit more similar cloacal bacterial communities than expected by chance? To answer these questions, we sampled the cloacal microbiome of adults during the breeding season and then used culture-independent, 16S rRNA gene amplicon sequencing to assess bacterial communities. Overall, we found that the cloacal bacterial communities of females and males were similar, and that the communities of pair-bonded social partners were not more similar than expected by chance. Our results suggest that social monogamy does not correlate with an increased similarity in cloacal bacterial community diversity or structure. As social partners were not assessed at the same time, it is possible that breeding stage differences masked social effects on bacterial community diversity and structure. Further, given that tree swallows exhibit high variation in rates of extra-pair activity, considering extra-pair activity when assessing cloacal microbial communities may be important for understanding how these bacterial communities are shaped. Further insight into how bacterial communities are shaped will ultimately shed light on potential tradeoffs associated with alternative behavioral strategies and socially-transmitted microbes.
宿主相关的微生物群落可以影响其动物宿主的整体健康，许多因素，包括行为和生理机能，都会影响这些复杂群落的形成。这些群落中的细菌可以通过间接（例如，共享环境）或直接（例如，身体接触）途径在个体之间通过社交进行传播。目前已经开展了一些研究来调查在交配背景下发生的社交互动如何塑造宿主相关的微生物群落。为了更好地理解这些相互作用，更具体地说，为了评估交配行为如何塑造动物的微生物组，我们研究了一种社会一夫一妻制但遗传上多配偶制的鸣禽——北美知更鸟（Tachycineta bicolor）的泄殖腔细菌群落。我们提出了两个问题：（1）在一个种群中，雌性和雄性知更鸟的泄殖腔细菌群落是否存在差异？（2）处于配对关系中的社交伙伴的泄殖腔细菌群落是否比随机预期的更相似？为了回答这些问题，我们在繁殖季节期间采样了成年知更鸟的泄殖腔微生物组，然后使用非培养的 16S rRNA 基因扩增子测序来评估细菌群落。总体而言，我们发现雌性和雄性知更鸟的泄殖腔细菌群落相似，并且配对关系中的社交伙伴的群落并不比随机预期的更相似。我们的研究结果表明，社会一夫一妻制与泄殖腔细菌群落多样性或结构的相似性增加无关。由于社交伙伴没有同时进行评估，因此繁殖阶段的差异可能掩盖了细菌群落多样性和结构上的社交影响。此外，由于知更鸟表现出额外配对活动的速率存在高度变化，在评估泄殖腔微生物群落时考虑额外配对活动可能对于理解这些细菌群落的形成方式很重要。进一步深入了解细菌群落的形成方式最终将阐明与替代行为策略和社交传播的微生物相关的潜在权衡。
