The dietary nutrient composition can affect insects' phenotypes by modulating their physiology. Furthermore, diet can affect gut microbiota composition and abundance, with indirect consequences for the host. In this study, we reared Drosophila melanogaster on five different diets; three with balanced sugar:yeast ratio, but with increasing caloric content (2:2, 8:8, 16:16, in weight %), and two with imbalanced sugar:yeast ratio, either with low sugar and high yeast content (2:16) or vice-versa (16:2). In each of these diets, we compared flies with conventional vs. artificially altered gut microbiota with antibiotics that reduced the bacterial load. The antibiotic treatment also had the surprising effect of increasing the amount of live yeast associated with the flies. We characterized flies from these ten treatments (5 diets × 2 microbiota) in terms of development, body mass, food preference, body reserves, metabolic rate and a range of stress tolerance traits (heat, cold, starvation and desiccation tolerance). Diets, and to a lesser extent antibiotic treatment, affected development rate, weight, and cold tolerance of adult flies. Other traits such as energy reserves, metabolic rate, food preference, or starvation tolerance were affected by diet alone. When detected, the effect of antibiotic treatment was stronger in yeast-poor diets, suggesting that gut bacterial community might help to counterbalance nutritional deficiencies. These results show that changes in dietary factors lead to a global re-organization of fly's physiology and development while the manipulation of gut microorganisms had minor effects that were mainly seen in case of protein restriction.

中文翻译：

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饮食中的营养平衡会影响果蝇与肠道菌群的表型性状。

饮食中的营养成分可以通过调节昆虫的生理状况来影响其表型。此外，饮食会影响肠道菌群的组成和丰度，对宿主产生间接影响。在这项研究中，我们以五种不同的饮食饲养了果蝇。三种糖/酵母比例均衡，但卡路里含量增加（以重量％计为2：2、8：8、16：16），另外两种糖/酵母比例不均衡，即糖含量低且酵母含量高（2 ：16），反之亦然（16：2）。在每种饮食中，我们将果蝇与传统的肠道菌群和人工降低的肠道菌群与降低细菌负荷的抗生素进行了比较。抗生素处理还具有令人惊奇的效果，其增加了与果蝇相关的活酵母的数量。我们从发育，体重，食物偏好，身体储备，代谢率和一系列胁迫耐受性特征（热，冷，饥饿和干燥耐受性）的角度对这十种治疗（5种饮食×2个微生物群）中的果蝇进行了表征。饮食，以及在较小程度上使用抗生素治疗，会影响成年果蝇的发育速度，体重和耐寒性。其他特征，例如能量储备，代谢率，食物偏爱或饥饿耐受性，仅受饮食影响。当检测到这种抗生素时，在酵母含量低的饮食中，抗生素治疗的效果更强，表明肠道细菌群落可能有助于抵消营养不足。这些结果表明，饮食因素的变化导致果蝇的全球重组。