Evolution of Metabolic Diversity in Animals

动物在能量使用和生产能力以及新陈代谢率方面差异巨大。物种的代谢率取决于它们的生活方式和栖息地，而进化过程塑造了这些差异。我的研究着眼于动物的代谢率以及潜在的生理生化特性为何以及如何进化。拟议研究的第一个目标将集中在涉及能源生产的细胞过程上。不仅动物的能源生产速度在进化，而且用于生产能源的燃料也因物种而异。蜜蜂和黄蜂等昆虫被认为是糖专家，但我们最近发现，它们利用氨基酸脯氨酸作为燃料产生能量的能力异常高。一些物种如何以及为什么进化出使用脯氨酸的能力尚不清楚。为了测试脯氨酸是否是大黄蜂飞行的重要燃料，我们将通过抑制脯氨酸代谢的中心酶来控制有脯氨酸和没有脯氨酸的花蜜饮食。此外，通过比较不同生活史策略的蜜蜂和黄蜂物种，我们将解决脯氨酸是否是越冬期间的能量来源。此外，这种方法将测试产生大量热量的物种是否使用代谢燃料更有效地产生热量。第二个目标是测试动物的体型如何推动新陈代谢率和潜在特征的进化。在昆虫中，身体和翅膀的大小影响翅拍频率和飞行肌肉收缩率，解释了代谢率的差异。为了了解动物的生理特性是如何与体重和翅膀大小共同进化的，我计划使用翅膀比例不同的果蝇。首先，苍蝇的大小和翅膀比例在很大程度上受发育过程中环境条件的影响，对飞行代谢率、飞行性能和肌肉功能的影响将被研究。下一步，将进行人工选择实验，进化出翅膀比例较大和较小的果蝇。这个实验将确定代谢率、飞行性能和肌肉功能是如何共同进化的。我们将通过育种实验和数量遗传学分析工具确定所研究性状的遗传基础。总之，这项工作将阐明动物如何利用和生产能量。建议的研究将涉及至少五名研究生和超过15名本科生，他们将使用进化生物学分析工具接受代谢生理学方面的培训。

Animals vary tremendously in their energy use and production capacity, their metabolic rate. The metabolic rate of species differs depending on their lifestyle and habitat, and evolutionary processes shape these differences. My research looks at why and how metabolic rate, and the underlying physiological and biochemical properties, evolve in animals. A first objective of the proposed research will focus on the cellular processes involved in energy production. Not only rates of energy production evolve in animals, but the fuels are used to produce energy also differ across species. Insects such as bees and wasps are thought to be sugar specialists, but we recently found an unusually high capacity to use the amino acid proline as a fuel to produce energy. How and why some species evolved the ability to use proline is unknown. To test whether proline is a substantial fuel used for flight in bumblebees, we will manipulate nectar diets with and without proline, and by inhibiting the central enzyme involved in proline metabolism. Furthermore, by comparing species of bees and wasps with diverse life-history strategies, we will address if proline is an energy source during overwintering. Also, this approach will test if species that generate a large amount of heat are doing so using metabolic fuels more efficient at heat production. A second objective will test how the size of animals drives the evolution of metabolic rate and underlying traits. In insects, body and wing size influence wingbeat frequency and flight muscle contraction rate, explaining differences in metabolic rate. To understand how the physiological properties of animals co-evolve with body mass and wing size, I plan on using fruit flies that differ in wing proportions. First, fly size and wing proportions can vary largely due to the influence of environmental conditions during development, and the consequences on flight metabolic rate, flight performance and muscle function will be studied. Next, artificial selection experiments will be conducted to evolve flies with larger and smaller wing proportions. This experiment will allow determining how metabolic rate, flight performance and muscle function co-evolve. We will determine the genetic basis of the traits studied by using breeding experiments and quantitative genetics analytical tools. Together this work will clarify how the use and production of energy evolve in animals. The proposed studies will involve at least five graduate students and over 15 undergraduates that will be trained in metabolic physiology using evolutionary biology analytical tools.