Costs, benefits and the evolution of inducible defences:: a case study with Daphnia pulex
Costs, benefits and the evolution of inducible defences:: a case study with Daphnia pulex
复制标题
DOI：
10.1111/j.1420-9101.2008.01520.x
复制
发表时间：
2008-05-01
影响因子：
2.1
通讯作者：
Beckerman, A. P.
中科院分区：
文献类型：
--
作者：
Hammill, E.;Rogers, A.;Beckerman, A. P.
表型可塑性是自然群体变异的主要来源之一。可诱导防御，这可以被认为是阈值性状，是一种形式的可塑性，产生生态和进化的后果。一个简单的成本效益模型支持这些阈值的维持和进化，诱导性状。在这个模型中，一个排名顺序开关预期的健身，定义的成本和收益之间的感应防御和不防御的变体，预测的风险水平，个人应诱导防御。在这里，捕食者诱导的形态防御蚤作为一个阈值特性，我们提供了第一次全面调查的成本和效益的阈值特性，以及它们如何结合联合收割机，以反映健身和预测的切换点，在诱导应该发生。我们开发的反应规范，显示在开关点的遗传变异。进一步的实验表明，诱导可以赋予生存的好处和成本方面的终身生殖成功。总之，这两个特质联合收割机估计预期的适应度，并可以预测之间的切换点不设防和防御战略。的预测相匹配的反应规范数据克隆的经验，这些成本和效益，以及对应的独立领域的数据诱导。然而，预测不，也不能，匹配克隆不获得诱导的好处。这项研究证实，一个简单的理论，生活史的成本和效益的基础上，是一个足够的框架，了解生态和诱导，阈值性状的进化。
Phenotypic plasticity is one major source of variation in natural populations. Inducible defences, which can be considered threshold traits, are a form of plasticity that generates ecological and evolutionary consequences. A simple cost-benefit model underpins the maintenance and evolution of these threshold, inducible traits. In this model, a rank-order switch in expected fitness, defined by costs and benefits of induction between defended and undefended morphs, predicts the risk level at which individuals should induce defences. Here, taking predator-induced morphological defences in Daphnia pulex as a threshold trait, we provide the first comprehensive investigation into the costs and benefits of a threshold trait, and how they combine to reflect fitness and predict the switchpoint at which induction should occur. We develop reaction norms that show genetic variation in switchpoints. Further experiments show that induction can confer a survival benefit and a cost in terms of lifetime reproductive success. Together, these two traits combine to estimate expected fitness and can predict the switchpoint between an undefended and a defended strategy. The predictions match the reaction norm data for clones that experience these costs and benefits, and correspond well to independent field data on induction. However, predictions do not, and cannot, match for clones that do not gain a benefit from induction. This study confirms that a simple theory, based on life history costs and benefits, is a sufficient framework for understanding the ecology and evolution of inducible, threshold traits.