Dietary restriction (DR), limiting calories or specific nutrients without malnutrition, extends lifespan across diverse taxa. Traditionally, this lifespan extension has been explained as a result of diet-mediated changes in the trade-off between lifespan and reproduction, with survival favoured when resources are scarce. However, a recently proposed alternative suggests that the selective benefit of the response to DR is the maintenance of reproduction. This hypothesis predicts that lifespan extension is a side effect of benign laboratory conditions, and DR individuals would be frailer and unable to deal with additional stressors, and thus lifespan extension should disappear under more stressful conditions. We tested this by rearing outbred female fruit flies (Drosophila melanogaster) on 10 different protein:carbohydrate diets. Flies were either infected with a bacterial pathogen (Pseudomonas entomophila), injured with a sterile pinprick or unstressed. We monitored lifespan, fecundity and measures of ageing. DR extended lifespan and reduced reproduction irrespective of injury and infection. Infected flies on lower protein diets had particularly poor survival. Exposure to infection and injury did not substantially alter the relationship between diet and ageing patterns. These results do not provide support for lifespan extension under DR being a side effect of benign laboratory conditions. This article is protected by copyright. All rights reserved.

中文翻译：

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测试果蝇饮食限制对寿命益处的进化解释（黑腹果蝇）

饮食限制 (DR)，在没有营养不良的情况下限制卡路里或特定营养素，可延长不同分类群的寿命。传统上，这种寿命延长被解释为饮食介导的寿命和繁殖之间权衡变化的结果，当资源稀缺时生存更有利于生存。然而，最近提出的替代方案表明，对 DR 反应的选择性好处是维持繁殖。该假设预测寿命延长是良性实验室条件的副作用，DR 个体会更虚弱，无法应对额外的压力，因此在压力更大的条件下，寿命延长应该会消失。我们通过在 10 种不同的蛋白质：碳水化合物饮食中饲养远交雌性果蝇（黑腹果蝇）来测试这一点。苍蝇要么感染了细菌病原体（昆虫假单胞菌），要么被无菌针刺伤，要么没有受到压力。我们监测了寿命、繁殖力和衰老测量。无论受伤和感染如何，DR 都延长了寿命并减少了繁殖。低蛋白质饮食的受感染果蝇存活率特别低。暴露于感染和损伤并没有显着改变饮食和衰老模式之间的关系。这些结果并不支持 DR 下的寿命延长是良性实验室条件的副作用。本文受版权保护。版权所有。无论受伤和感染如何，DR 都延长了寿命并减少了繁殖。低蛋白质饮食的受感染果蝇存活率特别低。暴露于感染和损伤并没有显着改变饮食和衰老模式之间的关系。这些结果并不支持 DR 下的寿命延长是良性实验室条件的副作用。本文受版权保护。版权所有。无论受伤和感染如何，DR 都延长了寿命并减少了繁殖。低蛋白质饮食的受感染果蝇存活率特别低。暴露于感染和损伤并没有显着改变饮食和衰老模式之间的关系。这些结果并不支持 DR 下的寿命延长是良性实验室条件的副作用。本文受版权保护。版权所有。