Data from: Sex and genotype effects on nutrient-dependent fitness landscapes in Drosophila melanogaster

The sexes perform different reproductive roles and have evolved sometimes strikingly different phenotypes. One focal point of adaptive divergence occurs in the context of diet and metabolism, and males and females of a range of species have been shown to require different nutrients to maximize their fitness. Biochemical analyses in Drosophila melanogaster have confirmed that dimorphism in dietary requirements is associated with molecular sex differences in metabolite titres. In addition, they also showed significant within-sex genetic variation in the metabolome. To date however, it is unknown whether this metabolic variation translates into differences in reproductive fitness. The answer to this question is crucial to establish whether genetic variation is selectively neutral or indicative of constraints on sex-specific physiological adaptation and optimization. Here we assay genetic variation in consumption and metabolic fitness effects by screening male and female fitness of thirty D. melanogaster genotypes across four protein-to-carbohydrate ratios. In addition to confirming sexual dimorphism in consumption and fitness, we find significant genetic variation in male and female dietary requirements. Importantly, these differences are not explained by feeding responses and probably reflect metabolic variation that, in turn, suggests the presence of genetic constraints on metabolic dimorphism.

两性行使不同的生殖功能，并演化出有时差异极为显著的表型。适应性分化的核心焦点之一便聚焦于饮食与代谢领域，已有研究证实，多个物种类群的雌雄个体需要不同的营养物质以最大化自身适合度（fitness）。针对黑腹果蝇（Drosophila melanogaster）的生化分析表明，饮食需求的性别二态性（sexual dimorphism）与代谢物滴度的分子性别差异存在显著关联。此外，该研究还揭示了雌雄个体各自内部的代谢组（metabolome）中存在显著的性别内遗传变异。然而截至目前，学界尚不清楚这类代谢变异是否会转化为生殖适合度的差异。该问题的答案对于判断遗传变异属于选择中性，还是反映了性别特异性生理适应与优化所受的限制，均至关重要。本研究通过在四种蛋白质-碳水化合物比例条件下，筛选30个黑腹果蝇品系的雌雄适合度，测定了摄食行为与代谢适合度效应中的遗传变异。除证实摄食行为与适合度存在性别二态性之外，本研究还发现雌雄个体的饮食需求均存在显著的遗传变异。值得注意的是，这类差异无法通过摄食响应加以解释，其大概率反映了代谢变异，而这反过来又暗示了代谢二态性存在遗传限制。