The microbiota influences the Drosophila melanogaster life history strategy

Organisms are locally adapted when members of a population have a fitness advantage in one location relative to conspecifics in other geographies. For example, across latitudinal gradients, some organisms may trade off between traits that maximize fitness components in one, but not both, of somatic maintenance or reproductive output. Latitudinal gradients in life history strategies are traditionally attributed to environmental selection on an animal's genotype, without any consideration of the possible impact of associated microorganisms (\"microbiota\") on life history traits. Here, we show in Drosophila melanogaster, a key model for studying local adaptation and life history strategy, that excluding the microbiota from definitions of local adaptation is a major shortfall. First, we reveal that an isogenic fly line reared with different bacteria varies the investment in early reproduction versus somatic maintenance. Next, we show that in wild fruit flies, the abundance of these same bact...当种群内的个体在某一地理区域相较于其他地理区域的同种个体具有适合度优势时，该生物即发生局部适应（local adaptation）。例如在纬度梯度（latitudinal gradients）中，部分生物可能会在不同性状间进行权衡：这些性状仅能最大化体细胞维持（somatic maintenance）或繁殖产出（reproductive output）中的某一类适合度组分，而非同时兼顾两者。传统上，生活史策略（life history strategies）的纬度梯度被归因于对动物基因型（genotype）的环境选择，完全未考虑共生微生物“菌群（microbiota）”对生活史性状的潜在影响。本研究以黑腹果蝇（Drosophila melanogaster）——研究局部适应与生活史策略的关键模式物种——为对象，证实若在局部适应的定义中排除菌群，则存在重大疏漏。首先，我们发现饲养于不同细菌环境的同基因果蝇品系，其早期繁殖与体细胞维持间的资源投资权衡会发生改变。其次，我们在野生果蝇中证实，这些相同细菌的丰度……