Natural Selection on Continuous Reaction Norms: Thermal Sensitivity of Feeding in Pieris Catepillars

对于大多数生物体来说，一个人完成重要任务--进食、生长、移动等--的好坏取决于他的体温。PI将性能与体温之间的关系称为热性能曲线。性能曲线是如何演变的？自然选择如何影响野外种群的表现曲线？对于性能曲线上的自然选择来说，偶尔暴露在极低或极高的温度下比经常暴露在良好的温度下更重要吗？拟议的研究通过研究卷心菜毛虫的生长和取食率的热性能曲线来解决这些问题，卷心菜毛虫是一种常见而广泛的蝴蝶物种，以各种本地和农业十字花科植物(包括卷心菜、羽衣甘蓝和相关蔬菜)为食。PI将在实验室测量热性能曲线的遗传变异模式，并确定性能曲线的变异如何影响实验羽衣甘蓝花园的存活率、世代时间和繁殖力。通过同时表征野外毛虫的身体温度，PI可以评估温度变化模式与生长和取食的热性能曲线选择之间的关系。然后，PI可以通过操纵花园中的温度变化(使用部分遮阳布)并测量热性能曲线上选择的变化来直接测试这种关系。这些研究将为现场热工性能曲线的选择提供首次研究。由于卷心菜是一种地理范围异常广泛的农业害虫(例如，它们发生在北美、欧洲、日本和澳大利亚的大部分地区)，这些研究也将增加我们对这种广泛存在的害虫物种的温度适应的了解：它如何能够容忍和适应这些不同地理区域经历的广泛温度范围？

For most organisms, how well an individual performs vital tasks- eating, growing, moving, etc-varies with that individual's body temperature. The PIs' call the relationship between performance and body temperature a thermal performance curve. How do performance curves evolve? How does natural selection act on performance curves for populations in the field? Is infrequent exposure to extreme low or high temperatures more important than frequent exposure to 'good' temperatures for natural selection on performance curves? The proposed research addresses these questions, by studying thermal performance curves for growth and feeding rates of caterpillars of the Cabbage White, a common and widespread butterfly species that feeds on a variety of native and agricultural crucifers (including cabbage, collards and related vegetables). The PIs' will measure patterns of genetic variation in thermal performance curves in the lab, and determine how variation in performance curves affects survival, generation time and fecundity in experimental collard gardens. By simultaneously characterizing caterpillar body temperatures in the field, the PIs can assess how patterns of temperature variation relate to selection on thermal performance curves for growth and feeding. The PIs can then directly test this relationship by manipulating temperature variation (using partial shade cloths) in the garden and measuring the changes in selection on thermal performance curves. These studies will provide the first studies of selection on thermal performance curves in the field. Because Cabbage Whites are an agricultural pest with unusually large geographic range (e.g. they occur throughout most of North America, Europe, Japan and Australia), these studies will also add to our understanding of temperature adaptation in this widespread pest species: How is it able to tolerate and adapt to the wide range of temperatures experienced in these different geographical areas?