Vertebrates harbor trillions of microorganisms in the gut, collectively termed the gut microbiota, which affect a wide range of host functions. Recent experiments in lab-reared vertebrates have shown that changes in environmental temperature can induce shifts in the gut microbiota, and in some cases these shifts have been shown to affect host thermal physiology. However, there is a lack of information about the effects of temperature on the gut microbiota of wild-caught vertebrates. Moreover, in ectotherms, which are particularly vulnerable to changing temperature regimens, the extent to which microbiota composition is shaped by temperature and associated with host thermal tolerance has not been investigated. To address these issues, we monitored the gut microbiota composition of wild-caught western fence lizards (Sceloporus occidentalis) experimentally exposed to a cool-to-warm temperature transition. Comparing experimentally exposed and control lizards indicated that warm temperatures altered and destabilized the composition of the S. occidentalis gut microbiota. Warming drove a significant reduction in the relative abundances of a clade of Firmicutes, a significant increase in the rate of compositional turnover in the gut microbiota within individual lizards, and increases in the abundances of bacteria from predicted pathogenic clades. In addition, the composition of the microbiota was significantly associated with the thermal tolerance of lizards measured at the end of the experiment. These results suggest that temperature can alter the lizard gut microbiota, with potential implications for the physiological performance and fitness of natural populations.

中文翻译：

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蜥蜴肠道微生物组随温度变化，并与耐热性相关。

脊椎动物在肠道中藏有数万亿个微生物，这些微生物统称为肠道微生物群，会影响多种宿主功能。最近在实验室饲养的脊椎动物中进行的实验表明，环境温度的变化会引起肠道菌群的变化，并且在某些情况下，这些变化已表明会影响宿主的热生理。但是，缺乏有关温度对野生捕捞脊椎动物肠道微生物群影响的信息。此外，在特别易受温度变化影响的等温线中，尚未研究微生物群组成受温度影响的程度以及与宿主热耐受性相关的程度。为了解决这些问题，我们监测了野生西栅栏蜥蜴的肠道菌群组成（钝顶孢（Scoloporus occidentalis）实验暴露于从凉到暖的温度转变。比较实验暴露的蜥蜴和对照蜥蜴，发现温暖的温度改变了西方链球菌肠道菌群的组成并使之不稳定。变暖显着降低了Firmicutes枝的相对丰度，极大地增加了单个蜥蜴内肠道菌群组成更新的速率，并增加了来自预期致病进化枝的细菌的丰度。此外，微生物群的组成与实验结束时测得的蜥蜴的耐热性显着相关。这些结果表明温度可以改变蜥蜴肠道菌群，对自然种群的生理表现和适应能力具有潜在的影响。