Data from: The combined effects of temporal autocorrelation and the costs of plasticity on the evolution of plasticity

Adaptive phenotypic plasticity is an important source of intraspecific variation, and for many plastic traits the costs or factors limiting plasticity seem cryptic. However, there are several different factors that may constrain the evolution of plasticity, but few models have considered costs and limiting factors simultaneously. Here we use a simulation model to investigate how the optimal level of plasticity in a population depends on a fixed fitness cost for maintaining a potential for plasticity or an incremental fitness cost for producing a plastic response in combination with environmental unpredictability (environmental fluctuation speed) limiting plasticity. Our model identifies two mechanisms that act, almost separately, to constrain the evolution of plasticity: 1) The fitness cost of plasticity scaled by the non-plastic environmental tolerance, and 2) the environmental fluctuation speed scaled by the rate of phenotypic change. That is, the evolution of plasticity is constrained by the high cost of plasticity in combination with high tolerance for environmental variation, or fast environmental changes in combination with slow plastic response. Qualitatively similar results are found when fixed and incremental fitness costs of plasticity are incorporated, although a larger degree of plasticity is selected for with an incremental cost. Our model highlights that it is important to consider direct fitness costs and phenotypic limitations in relation to non-plastic environmental tolerance and environmental fluctuations, respectively, to understand what constrains the evolution of phenotypic plasticity.

适应性表型可塑性（adaptive phenotypic plasticity）是种内变异的重要来源，针对多数可塑性性状，制约其可塑性的成本或相关因子往往较为隐蔽。然而，尽管已有多种不同因子可能制约可塑性的演化，但鲜有模型能够同时兼顾可塑性成本与限制因子两类因素。本研究采用模拟模型，探究种群的最优可塑性水平如何受两类因素共同影响：一是维持可塑性潜能所需的固定适合度成本，或是产生可塑性响应所需的增量适合度成本；二是与环境不可预测性（即环境波动速率）相关的可塑性限制条件。本模型识别出两种几乎独立发挥作用的可塑性演化制约机制：其一为可塑性适合度成本与非可塑性环境耐受度的标度关联；其二为环境波动速率与表型变化速率的标度关联。换言之，当可塑性成本高昂且物种对环境变异的耐受度较高时，或是环境变化快速但表型响应滞后时，可塑性的演化均会受到制约。当同时纳入可塑性的固定与增量适合度成本时，可得到定性一致的结果，不过在增量成本模式下，会筛选出更高程度的可塑性。本研究强调，若要明晰制约表型可塑性演化的核心因素，需分别结合非可塑性环境耐受度与环境波动，考量直接适合度成本与表型限制条件。