Department of Biology, CB-3280, University of North Carolina, Chapel Hill, North Carolina 27599.
Integr Comp Biol. 2003 Jul;43(3):470-7. doi: 10.1093/icb/43.3.470.
Many aspects of physiological and organismal performance vary with some continuous environmental variable: e.g., photosynthetic rate as a function of light intensity; growth rate or sprint speed as a function of temperature. For such 'performance curves', the environment plays two roles: it affects both the levels of performance expressed, and the relationship between performance and fitness. How does environmental variation within a generation determine natural selection on performance curves? We describe an approach to this question that has three components. First, we quantify natural environmental variation and assess its impact on performance in the field. Second, we develop a simple theoretical model that predicts how fine-grained environmental variation determines selection on performance curves. Third, we describe how directional selection on performance curves may be estimated and compared to theoretical predictions. We illustrate these steps using data on performance curves of short-term growth rate as a function of temperature (thermal performance curves) in Pieris caterpillars. We use this approach to explore whether selection acts primarily on growth rate at specific temperatures, or on more integrated aspects of growth.
例如，光合作用率随光强度的变化；增长率或冲刺速度随温度的变化。对于这样的“表现曲线”，环境起了两个作用：它既影响表现的水平，也影响表现与适应性之间的关系。在一代之内，环境变化如何决定对表现曲线的自然选择？我们描述了一种解决这个问题的方法，它有三个组成部分。首先，我们量化自然环境变化，并评估其对野外表现的影响。其次，我们开发了一个简单的理论模型，预测细粒度的环境变化如何决定对表现曲线的选择。第三，我们描述了如何估计和比较对表现曲线的定向选择，并进行理论预测。我们使用在 Pieris 毛虫的短期增长率作为温度的函数（热表现曲线）的表现曲线数据来说明这些步骤。我们使用这种方法来探索选择是主要作用于特定温度下的增长率，还是更综合的生长方面。
