Evolutionary conflict over animal nutrition and diet choice

动物营养学研究的最新进展产生了显著的发现。在许多物种中，影响健康的不仅仅是食物的量，还有食物中的蛋白质和碳水化合物含量。特别是，相对高蛋白和低碳水化合物的饮食可以促进生殖，而低蛋白质和高碳水化合物的饮食可以延长寿命。这些结果往往导致一种理想的饮食结构使物种的繁殖最大化，另一种饮食结构使人的寿命最大化，这是对人类健康的强烈兴趣的结果。然而，我们目前对理想饮食的理解仅限于过于简单的实验室条件。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不会转化为包括人类在内的所有有机体在现实世界中经历的复杂环境。特别是，动物的交配频率可能会极大地影响其营养需求，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值是如何随着交配而改变的知之甚少，也不知道个体如何在与配偶和家人在营养问题上存在利益冲突的情况下实现他们的饮食最佳值。我的研究目的是通过将进化的观点引入营养生态学来解决这一差距。我的目标是发现最大化健康、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的变化而变化。我将使用果蝇黑腹果蝇，这是一种实验上容易驯服的动物，它与包括人类在内的脊椎动物分享了大部分营养生理学，使我能够在实验中直接测试营养假说，而这些实验在人类受试者身上是不可行的。通过这项研究，我将专注于三个问题：最大化寿命和生殖的饮食如何随着交配频率的变化而变化；进化的利益冲突在多大程度上--例如，当母亲的最佳饮食与她们的后代不同--决定了他们的饮食偏好；以及男性可能通过什么机制影响他们配偶的营养偏好。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.