Macronutrient intake impacts physiology, behavior, physiology and gene expression in a wide range of organisms. We used the response surface methodology to compare how life history traits, lifespan and reproduction differ as a function of protein and carbohydrate intakes under choice and no-choice feeding regimens in the fruit fly, Drosophila melanogaster. We found that when offered a choice of nutritionally complementary foods mated female flies regulated towards a protein to carbohydrate ratio (P:C) that was associated with shortened lifespan and maximal egg production when compared to response surfaces derived from flies fed one of a range of fixed diets differing in P:C (no-choice regimen). This difference in lifespan between choice and no-choice feeding was not seen in males or virgin flies, reflecting the fact that increased protein intake is triggered by mating to support egg production. However, whereas in mated females a higher P:C intake was associated with greater egg production under both choice and no-choice feeding, contrary to expectations, choice-fed mated flies laid fewer eggs than no-choice flies on equivalent macronutrient intakes, perhaps reflecting that they had to ingest twice the volume of food to attain an equivalent intake of nutrients than no-choice flies on diet of equivalent P:C ratio.

中文翻译：

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果蝇的生活史权衡：果蝇选择饮食以牺牲寿命为代价最大化繁殖

大量营养素的摄入会影响多种生物体的生理、行为、生理和基因表达。我们使用响应面方法来比较果蝇果蝇的生活史特征、寿命和繁殖在选择和非选择喂养方案下作为蛋白质和碳水化合物摄入量的函数的差异。我们发现，当给交配的雌性果蝇提供一种营养补充食物的选择时，其蛋白质与碳水化合物的比例（P:C）会受到调节，与喂养一系列食物之一的果蝇的反应表面相比，该比例与寿命缩短和最大产蛋量相关。 P:C 不同的固定饮食（无选择方案）。在雄性或处女果蝇中没有发现选择喂养和非选择喂养之间的寿命差异，这反映出交配触发蛋白质摄入量增加以支持产卵这一事实。然而，尽管在交配雌性中，较高的 P:C 摄入量与选择喂养和非选择喂养下更高的产蛋量相关，但与预期相反，选择喂养的交配果蝇在同等常量营养素摄入量下比非选择果蝇产下的鸡蛋更少，也许这表明，与采用同等 P:C 比例饮食的无选择果蝇相比，它们必须摄入两倍量的食物才能获得同等的营养摄入量。