Evolutionary conflict over animal nutrition and diet choice

动物营养研究的最新进展产生了显著的发现。在许多物种中，影响健康的不仅是食物的摄入量，还有食物中的蛋白质和碳水化合物含量。特别是，高蛋白和低碳水化合物的饮食可以促进生殖，而低蛋白和高碳水化合物的饮食可以延长寿命。这些结果通常会导致一种理想的饮食组成，使物种的繁殖最大化，另一种饮食组成，使寿命最大化，这是对人类健康的浓厚兴趣的结果。然而，我们目前对理想饮食的理解仅限于过于简化的实验室条件。这是一个问题，因为在良性和稳定的条件下最大化繁殖和寿命的饮食组成可能无法转化为包括人类在内的所有生物在现实世界中所经历的复杂环境。特别是，动物的交配频率可能会强烈影响其营养需求，因为在许多物种中，交配频率的增加与繁殖和寿命的增加有关。我们目前对营养偏好和最佳状态是如何随着交配而改变的知之甚少，也不知道尽管与配偶和家庭成员在营养方面存在利益冲突，但个体如何实现最佳饮食状态。我的研究目标是通过将进化的视角引入营养生态学来解决这一差距。我的目标是发现最大限度地提高健康，寿命和繁殖的饮食如何随着动物所经历的生态和社会环境而变化。我将使用果蝇，一种实验上易于控制的动物，它的大部分营养生理与脊椎动物（包括人类）相同，使我能够直接测试在人类实验对象中不可行的营养假设。在这项研究中，我将重点关注三个问题：最大化寿命和繁殖能力的饮食如何随着交配频率的变化而变化；进化上的利益冲突在多大程度上塑造了饮食偏好——例如，当母亲的最佳饮食与子女的不同时；男性通过什么机制影响其配偶的营养偏好？这项工作有可能有助于我们对动物适应的基本了解，并有可能改善人类和其他动物的健康、寿命或生殖能力。

Recent advances in animal nutrition research have produced remarkable findings. Across many species, it is not only the amount of food eaten but also the protein and carbohydrate content of that food that influences health. In particular, diets that are relatively high in protein and low in carbohydrate diets enhance reproduction, whereas low protein and high carbohydrate diets prolong life. These results often lead to a picture of an ideal diet composition that maximizes a species' reproduction and another diet composition that maximizes lifespan, a result of keen interest for human health. However, our current understanding of the ideal diet is limited to overly simplified laboratory conditions. This is a problem because the diet compositions that maximize reproduction and lifespan in benign and stable conditions might not translate to the complex environments that all organisms, including humans, experience in the real world. In particular, an animal's mating frequency might strongly affect its nutritional needs, because increased mating frequency is associated with increased reproduction and lifespan in many species. We currently know little about how nutritional preferences and optima shift in response to mating, or about how individuals can achieve their dietary optima despite conflicts of interest over nutrition with their mates and family members.The goal of my research is to address this gap by bringing an evolutionary perspective to nutritional ecology. I aim to discover how the diets that maximize health, lifespan and reproduction vary with the ecological and social settings that animals experience. I will use the fruit fly Drosophila melanogaster, an experimentally tractable animal that shares most of its nutritional physiology with vertebrates - including humans - to enable me to directly test nutritional hypotheses in experiments that are not feasible with human subjects. With this research I will focus on three questions: how diets that maximize lifespan and reproduction change with mating frequency; to what extent evolutionary conflicts of interest - for example, when mothers have different optimal diets from their offspring - shapes dietary preferences; and by what mechanisms might males influence the nutritional preferences of their mates. This work has the potential to contribute to our basic understanding of animal adaptation and to the potential for improving the health, lifespan or reproductive capacity of humans and other animals.