Data from: Host diet mediates a negative relationship between abundance and diversity of Drosophila gut microbiota

Nutrient supply to ecosystems has major effects on ecological diversity, but it is unclear to what degree the shape of this relationship is general versus dependent on the specific environment or community. Although the diet composition in terms of the source or proportions of different nutrient types is known to affect gut microbiota composition, the relationship between the quantity of nutrients supplied and the abundance and diversity of the intestinal microbial community remains to be elucidated. Here we address this relationship using replicate populations of Drosophila melanogaster maintained over multiple generations on three diets differing in the concentration of yeast (the only source of most nutrients). While a 6.5-fold increase in yeast concentration led to a 100-fold increase in the total abundance of gut microbes, it caused a major decrease in their alpha diversity (by 45-60 % depending on the diversity measure). This was accompanied by only minor shifts in the taxonomic affiliation of the most common operational taxonomic units (OTUs). Thus, nutrient concentration in host diet mediates a strong negative relationship between the nutrient abundance and microbial diversity in the Drosophila gut ecosystem.

生态系统的养分供给对生物多样性具有显著调控作用，但目前仍不明确该关联的模式在多大程度上具备普适性，又或是依赖于特定环境或群落特征。尽管已知不同营养类型的来源与比例所构成的饮食组成，会对肠道微生物群的结构产生影响，但养分供给总量与肠道微生物群落的丰度及多样性之间的具体关联，仍有待进一步阐明。本研究以黑腹果蝇（Drosophila melanogaster）的重复种群为实验材料，将其在以酵母为多数营养唯一来源、且酵母浓度存在差异的三种日粮中连续培养多代，以此探究上述关联。实验结果显示，当酵母浓度提升6.5倍时，肠道微生物的总丰度增长了100倍，但微生物的α多样性却出现显著下降——根据多样性指标的不同，下降幅度介于45%至60%之间。与此同时，最常见的操作分类单元（Operational Taxonomic Units，OTUs）的分类学归属仅发生了小幅偏移。综上，宿主日粮中的养分浓度介导了果蝇肠道生态系统内，养分丰度与微生物多样性之间的强负相关关系。