Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, New York, USA
Biological Sciences Department, California Polytechnic State University, San Luis Obispo, California, USA.
Appl Environ Microbiol. 2020 Aug 18;86(17). doi: 10.1128/AEM.01181-20.
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 () 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 gut microbiota. Warming drove a significant reduction in the relative abundances of a clade of , 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. Gut microbial communities affect their animal hosts in numerous ways, motivating investigations of the factors that shape the gut microbiota and the consequences of gut microbiota variation for host traits. In this study, we tested the effects of increases in environmental temperatures on the gut microbiota of fence lizards, a vertebrate ectotherm threatened by warming climates. By monitoring lizards and their gut microbes during an experimental temperature treatment, we showed that the warming altered and destabilized the lizard gut microbiota. Moreover, measuring thermal performance of lizard hosts at the end of the experiment indicated that the composition of the gut microbiota was associated with host thermal tolerance. These results indicate that warming temperatures can alter the gut microbiota of vertebrate ectotherms and suggest relationships between variation in the gut microbiota and the thermal physiology of natural host populations.
脊椎动物的肠道中栖息着数万亿种微生物，统称为肠道微生物群，这些微生物会影响宿主的多种功能。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微生物群的转移，在某些情况下，这些转移会影响宿主的热生理学。然而，关于温度对野生捕获的脊椎动物肠道微生物群的影响，我们知之甚少。此外，在变温动物中，温度变化对其影响尤其大，但是微生物群的组成在多大程度上受到温度的影响，以及与宿主的热耐受性有何关联，这些问题尚未得到研究。为了解决这些问题，我们监测了实验中暴露于凉爽到温暖温度过渡的野生捕获的西部栅栏蜥蜴的肠道微生物群组成。比较实验暴露组和对照组蜥蜴表明，温暖的温度改变并破坏了肠道微生物群的组成。变暖导致一个属的相对丰度显著减少，个体蜥蜴肠道微生物群的组成周转率显著增加，预测的致病性属的细菌丰度增加。此外，微生物群的组成与实验结束时测量的蜥蜴的热耐受性显著相关。这些结果表明，温度可以改变蜥蜴的肠道微生物群，这可能对自然种群的生理表现和适应性有影响。肠道微生物群落以多种方式影响其动物宿主，这促使人们研究塑造肠道微生物群的因素以及肠道微生物群变化对宿主特征的影响。在这项研究中，我们测试了环境温度升高对栅栏蜥蜴肠道微生物群的影响，栅栏蜥蜴是一种受变暖气候威胁的脊椎动物变温动物。通过在实验温度处理过程中监测蜥蜴及其肠道微生物，我们发现变暖改变并破坏了蜥蜴的肠道微生物群。此外，在实验结束时测量蜥蜴宿主的热性能表明，肠道微生物群的组成与宿主的热耐受性有关。这些结果表明，变暖的温度可以改变脊椎动物变温动物的肠道微生物群，并表明肠道微生物群的变化与自然宿主种群的热生理学之间存在关系。
