Evolution of a predator-induced, nonlinear reaction norm

Inducible, anti-predator traits are a classic example of phenotypic plasticity. Their evolutionary dynamics depend on their genetic basis, the historical pattern of predation risk that populations have experienced and current selection gradients. When populations experience predators with contrasting hunting strategies and size preferences, theory suggests contrasting micro-evolutionary responses to selection. Daphnia pulex is an ideal species to explore the micro-evolutionary response of anti-predator traits because they face heterogeneous predation regimes, sometimes experiencing only invertebrate midge predators and other times experiencing vertebrate fish and invertebrate midge predators. We explored plausible patterns of adaptive evolution of a predator-induced morphological reaction norm. We combined estimates of selection gradients that characterize the various habitats that D. pulex experiences with detail on the quantitative genetic architecture of inducible morphological defen...诱导型抗捕食性状是表型可塑性（phenotypic plasticity）的经典范例。其演化动态取决于自身的遗传基础、种群所经历的捕食风险历史模式，以及当前的选择梯度（selection gradients）。当种群面临具有迥异捕食策略与体型偏好的捕食者时，理论预测其会呈现出差异化的微演化选择响应。蚤状溞（Daphnia pulex）是探究抗捕食性状微演化响应的理想模式物种：它们所处的捕食环境存在异质性，有时仅会遭遇无脊椎摇蚊捕食者，有时则同时面临脊椎动物鱼类与无脊椎摇蚊捕食者。本研究探究了捕食诱导型形态反应规范（morphological reaction norm）的潜在适应性演化模式。我们结合了用以表征蚤状溞所经历的各类生境的选择梯度估算结果，以及诱导型形态防御的数量遗传结构的详细信息...