Crane Phylosymbiosis Data Files from A bird's-eye view of phylosymbiosis: weak signatures of phylosymbiosis among all 15 species of cranes

In numerous animal clades, the evolutionary history of host species drives patterns of gut microbial community structure, resulting in more divergent microbiota with increasing phylogenetic distance between hosts. This phenomenon, termed phylosymbiosis, has been observed in diverse evolutionary lineages, but has been difficult to detect in birds. Previous tests of phylosymbiosis among birds have been conducted using wild individuals, and thus interspecific differences in diet and environment may have masked a phylogenetic signal. Therefore, we tested for phylosymbiosis among all 15 species of cranes (family Gruidae) housed in the same captive environment and maintained on identical diets. 16S rRNA sequencing revealed that crane species harbour distinct gut microbiota. Overall, we detected marginally significant patterns of phylosymbiosis, the strength of which was increased when including the estimates of absolute microbial abundance (rather than relative abundance) derived from microbial densities determined by flow cytometry. Using this approach, we detected the statistically significant signatures of phylosymbiosis only after removing male cranes from our analysis, suggesting that using mixed-sex animal cohorts may prevent the detection of phylosymbiosis. Though weak compared with mammals (and especially insects), these results provide evidence of phylosymbiosis in birds. We discuss the potential differences between birds and mammals, such as transmission routes and host filtering, that may underlie the differences in the strength of phylosymbiosis.

在众多动物支系中，宿主物种的演化历史塑造了肠道微生物群落结构模式，宿主间的系统发育距离越远，其肠道微生物组的差异就越大。这一现象被称为系统发育共生（phylosymbiosis），已在多种演化支系中被观测到，但在鸟类中却难以被检测到。此前针对鸟类的系统发育共生检验均使用野生个体开展，因此物种间饮食与环境的差异可能掩盖了系统发育信号。为此，我们对饲养于同一笼养环境、饲喂相同日粮的所有15种鹤科（Gruidae）鹤类开展了系统发育共生检验。16S核糖体RNA（16S rRNA）测序结果显示，不同鹤类物种拥有独特的肠道微生物组。总体而言，我们检测到了边缘显著的系统发育共生模式；当引入通过流式细胞术（flow cytometry）测定的微生物密度推导得到的绝对微生物丰度（而非相对丰度）估算值时，该模式的显著性得到增强。采用该方法后，我们仅在剔除雄性鹤类样本后才检测到具有统计学显著性的系统发育共生特征，这表明使用混合性别的动物队列可能会阻碍系统发育共生的检出。尽管与哺乳动物（尤其是昆虫）相比，该信号强度较弱，但本研究结果为鸟类存在系统发育共生现象提供了证据。我们还探讨了鸟类与哺乳动物之间可能存在的潜在差异（如传播途径与宿主过滤机制），这些差异或可解释二者在系统发育共生强度上的不同。