International Research Fellowship Program: Nutritional Ecology and the Evolution of Seasonal Color Polymorphism in a Butterfly

[07544887]莫尔豪斯国际研究奖学金计划使美国科学家和工程师能够到国外进行9到24个月的研究。该计划的奖励为联合研究提供了机会，并利用独特或互补的设施、专业知识和国外的实验条件。该奖项将支持Nathan I. Morehouse博士与法国图尔大学Jerome Casas博士进行为期24个月的研究。大型彩色装饰品是自然界中最引人注目的特征之一，但它们的生产和进化的许多方面仍然知之甚少。例如，除了少数几种动物外，我们对产生颜色图案的成本和生理权衡的理解仍然不完整。无脊椎动物的着色尤其如此，它们代表了动物王国中一些色彩最明显的成员。PI正在利用欧洲地图蝴蝶（Araschnia levana）在进化框架内更好地了解颜色的成本，这种蝴蝶以其两种季节性颜色变化而闻名，一种是亮橙色的春季变化，另一种是黑白相间的夏季变化。虽然这两种颜色在视觉上是不同的，但它们的颜色模式在生物化学上可能更加不同。春季变形的翅膀图案需要合成和沉积大量的橙色单色色素，而夏季变形则需要大量的黑色素来产生翅膀图案。这两种色素的合成需要不同的基本营养物质：同色色素需要氨基酸色氨酸，而黑色素则由酪氨酸和/或苯丙氨酸合成。这些基本的生化差异很可能对与每种颜色形态产生相关的生理机制和权衡产生强烈影响。他正在研究构成紫叶藓发育基础的营养动力学。该研究旨在量化1)可用资源的季节性变化，2)养分吸收的季节性差异，3)养分分配的季节性差异以及由此产生的生活史权衡，以及4)蜕皮激素和/或幼体激素在调节生长组织之间争夺色彩产生资源中的作用。他的工作结果将使我们更好地理解这种颜色多态性的进化，也许更普遍地理解颜色特征。

0754487MorehouseThe International Research Fellowship Program enables U.S. scientists and engineers to conduct nine to twenty-four months of research abroad. The program's awards provide opportunities for joint research, and the use of unique or complementary facilities, expertise and experimental conditions abroad.This award will support a twenty-four month research fellowship by Dr. Nathan I. Morehouse to work with Dr. Jerome Casas at the University of Tours in France.Large color ornaments are some of the most eye-catching traits in the natural world, and yet many aspects of their production and evolution remain poorly understood. For example, in all but a select few animal species, our understanding of the costs and physiological tradeoffs associated with producing color patterns is still incomplete. This is particularly true for coloration in invertebrates, which represent some of the most conspicuously colored members of the animal kingdom. The PI is working to better understand the costs of coloration within an evolutionary framework using the European Map Butterfly, Araschnia levana, a butterfly species known for its two seasonal color morphs, a bright orange spring morph and a black-and-white summer morph. While these two color morphs are distinct visually, their color patterns are perhaps even more different biochemically. The wing patterns of the spring morph require the synthesis and deposition of large amounts of orange ommochrome pigments, whereas the summer morph uses large amounts of melanin pigments to produce its wing patterns. These two pigment types draw on different pools of basic nutrients for their synthesis: ommochromes require the amino acid tryptophan, whereas melanin is synthesized from tyrosine and/or phenylalanine. Such basic biochemical differences are likely to have a strong influence on the physiological mechanisms and tradeoffs associated with the production of each color morph. He is investigating the nutrient dynamics that underlie the development of A. levana?s two color morphs, seeking to quantify 1) seasonal variation in available resources, 2) seasonal differences in nutrient uptake, 3) differences between seasonal morphs in nutrient allocation and resulting life-history tradeoffs, and 4) the role of ecdysone and/or juvenile hormone in mediating competition between growing tissues for resources involved in color production. Results from his work will allow us to better understand the evolution of this color polymorphism, and perhaps color traits more generally.