Studies of how the microbiome varies among individuals, populations, and abiotic conditions are critical for understanding this key component of an organism's biology and ecology. In the case of Daphnia, aquatic microcrustaceans widely used in population/community ecology and environmental science studies, understanding factors that influence microbiome shifts among individuals is useful for both basic and applied research contexts. In this study, we assess differences in the microbiome among genotypes of D. magna collected from three regions along a large latitudinal gradient (Finland, Germany, and Israel). After being reared in the lab for many years, we sought to characterize any differences in genotype- or population-specific microbial communities, and to assess whether the microbiota varied among temperatures. Our study is similar to a recent comparison of the microbial communities among D. magna genotypes raised in different temperatures published by Sullam et al. (Microb Ecol 76(2):506-517, 2017), and as such represents one of the first examples of a reproducible result in microbiome research. Like the previous study, we find evidence for a strong effect of temperature on the microbiome of D. magna, although across a much smaller temperature range representing potential near-future climates. In addition, we find evidence that the microbiomes of D. magna genotypes from different regions are distinct, even years after being brought into the laboratory. Finally, our results highlight a potentially common finding in the expanding area of microbiome research-differences among treatments are not necessarily observed in the most abundant taxonomic groups. This highlights the importance of considering sampling scheme and depth of coverage when characterizing the microbiome, as different experimental designs can significantly impact taxon-specific results, even when large-scale effects are reproduced.

中文翻译：

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大型水蚤相关基因型，种群和温度的微生物群变化。

研究微生物组在个体，群体和非生物条件之间如何变化对于了解生物体生物学和生态学的这一关键组成部分至关重要。就水蚤类甲壳纲水蚤而言，它广泛用于人口/社区生态学和环境科学研究中，了解影响个体间微生物组迁移的因素对于基础研究和应用研究都是有用的。在这项研究中，我们评估了沿大纬度梯度（芬兰，德国和以色列）从三个地区收集的D. magna基因型之间的微生物组差异。在实验室中饲养多年后，我们试图表征基因型或种群特异性微生物群落的任何差异，并评估微生物群是否随温度变化。我们的研究与Sullam等人在不同温度下升高的D. magna基因型之间微生物群落的最新比较相似。（Microb Ecol 76（2）：506-517，2017），因此代表了微生物组研究中可再现结果的首批实例之一。像以前的研究一样，我们发现证据表明温度对D. magna微生物组具有很强的影响，尽管在较小的温度范围内代表潜在的近期气候。此外，我们发现证据表明，即使在进入实验室数年之后，来自不同地区的D. magna基因型的微生物组也是不同的。最后，我们的结果凸显了微生物组研究领域不断扩大的潜在共同发现-在最丰富的分类组中不一定观察到治疗之间的差异。