Evolution of Metabolic Diversity in Animals

动物在能量利用、生产能力和代谢率方面差异很大。物种的代谢率因其生活方式和栖息地而异，进化过程塑造了这些差异。我的研究着眼于为什么和如何代谢率，以及潜在的生理和生化特性，在动物中进化。 拟议研究的第一个目标将集中在参与能源生产的细胞过程。不仅动物的能量生产率会进化，而且用于生产能量的燃料也会因物种而异。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何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，我们将通过抑制参与脯氨酸代谢的中心酶来操纵含有和不含脯氨酸的花蜜饮食。此外，通过比较具有不同生活史策略的蜜蜂和黄蜂的种类，我们将讨论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。 第二个目标将测试动物的大小如何驱动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，解释代谢率的差异。为了了解动物的生理特性是如何与身体质量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，由于发育过程中环境条件的影响，苍蝇的大小和翅膀的比例可能会有很大变化，将研究其对飞行代谢率、飞行性能和肌肉功能的影响。接下来，将进行人工选择实验，以进化出翅膀比例更大和更小的苍蝇。这项实验将允许确定代谢率，飞行性能和肌肉功能如何共同进化。我们将通过育种实验和数量遗传学分析工具来确定所研究性状的遗传基础。这项工作将阐明动物如何使用和生产能量。 拟议的研究将涉及至少5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.