The importance of climate, habitat structure, and higher trophic levels on microbial diversity is only beginning to be understood. Here, we examined the influence of climate variables, plant morphology, and the abundance of aquatic invertebrates on the microbial biodiversity of the northern pitcher plant Sarracenia purpurea. The plant's cup‐shaped leaves fill with rainwater and support a miniature, yet full‐fledged, ecosystem with a diverse microbiome that decomposes captured prey and a small network of shredding and filter‐feeding aquatic invertebrates that feed on microbes. We characterized pitcher microbiomes of 108 plants sampled at 36 sites from Florida to Quebec. Structural equation models revealed that annual precipitation and temperature, plant size, and midge abundance had direct effects on microbiome taxonomic and phylogenetic diversity. Climate variables also exerted indirect effects through plant size and midge abundance. Further, spatial structure and climate influenced taxonomic composition, but not phylogenetic composition. Our results suggest that direct effects of midge abundance and climate and indirect effects of climate through its effect on plant‐associated factors lead to greater richness of microbial phylotypes in warmer, wetter sites.

中文翻译：

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环境-宿主-微生物相互作用在大陆规模上影响了紫草菌群

气候，生境结构和较高营养水平对微生物多样性的重要性才刚刚开始被理解。在这里，我们研究了气候变量，植物形态以及水生无脊椎动物的数量对北部捕虫草紫草的微生物多样性的影响。。该植物的杯状叶子充满了雨水，并支持一个微型而完整的生态系统，其中的微生物群落多种多样，可以分解捕获的猎物，并有一个破碎的，过滤的，以微生物为食的水生无脊椎动物网络。我们表征了从佛罗里达州到魁北克的36个地点采样的108种植物的投手微生物。结构方程模型表明，年降水量和温度，植物大小和蚊虫的丰富度对微生物组的分类学和系统发育多样性具有直接影响。气候变量还通过植物大小和蚊虫丰富度产生间接影响。此外，空间结构和气候影响分类学组成，但不影响系统发育组成。