Global warming impacts animal fitness, leading to increasing extinction risk in ectotherm species. Gut microbiota can contribute to host physiology leading to an increase of resistance to abiotic stress conditions. Temperature has profound effects on ectotherms and gut microbiota can influence cold and heat tolerance of ectotherm species. Additionally, the gut microbiota is sensitive to environmental temperature, which induces changes in its composition and diversity. Here, we investigated the role of the gut microbiota on heat tolerance of Drosophila subobscura comparing the knockdown time between conventional and axenic, and we also assessed the impact of heat stress on the diversity and community structure of the gut microbiota, comparing non-stressed and heat-stressed flies. Our findings provide evidence that gut microbiota influences heat tolerance, and that heat stress modifies the gut microbiota at taxonomical and structural levels. These results demonstrate that gut microbiota contributes to heat tolerance but it is also highly sensitive to transient heat stress, which could have important effects on host fitness, population risk extinction, and vulnerability of ectotherms to current and future climatic conditions.

中文翻译：

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果蝇的肠道菌群有助于其耐热性，但对瞬态热胁迫敏感。

全球变暖影响动物的适应能力，导致增加了外热物种的灭绝风险。肠道菌群可以促进宿主生理，导致对非生物胁迫条件的抵抗力增加。温度对放热具有深远的影响，肠道菌群可以影响放热物种的耐寒性和耐热性。另外，肠道菌群对环境温度敏感，这会引起其组成和多样性的变化。在这里，我们调查了肠道菌群对果蝇亚耐热的耐热性的作用比较常规和未成熟果蝇的击倒时间，我们还评估了热应激对肠道菌群多样性和群落结构的影响，比较了无应激果蝇和热应激果蝇。我们的发现提供了证据，即肠道菌群会影响耐热性，并且热应激会在分类学和结构水平上改变肠道菌群。这些结果表明，肠道菌群有助于提高耐热性，但对瞬态热应激也高度敏感，这可能对寄主适应性，种群灭绝风险以及外热对当前和未来气候条件的脆弱性具有重要影响。