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 a...

生态系统的养分供给对物种多样性具有显著影响，但目前尚不清楚这种养分供给与生态多样性之间的关系模式，在多大程度上具有普适性，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或占比所构成的日粮组成会影响肠道微生物群组成，但养分供给量与肠道微生物群落的丰度和多样性之间的关联仍有待阐明。本研究以黑腹果蝇（Drosophila melanogaster）的重复种群为研究对象，将其在以酵母为多数营养的唯一来源、且酵母浓度各不相同的三种日粮中维持多代，以此探究上述关联。尽管酵母浓度提升6.5倍会使肠道微生物总丰度增加至原来的100倍，但却会显著降低其α多样性（根据多样性衡量指标的不同，降幅可达45%至60%）。与此同时，肠道微生物的分类学组成仅发生小幅变化……