Insect Herbivory Density and Variable Selection on Components of Plant Defense

植物对食草病的防御可分为两种类型。一些性状会影响食草动物在植物上定居并吃掉植物的可能性，这些性状被称为抗性。其他特征影响生理调节，以减轻损害的不利影响，称为耐受性。防御性状对植物适合度的影响不是一成不变的，而是随着食草动物种群密度的消长而变化。从理论上讲，植物防御的选择可以分析为对防御成分的反应标准的选择。为了验证这一理论，通过实验来确定(1)抗性和耐性对植物适合度的贡献是如何随食草动物密度的变化而变化的，以及(2)是否存在随食草动物密度变化的抗性和耐性之间的权衡。本次调查将使用当地杂草黄花(Solidago Altissima)。基因复制体将被种植在草食动物种群密度或侵染水平受到控制的地块。这一结果将揭示防御成分的选择对食草动物种群密度的敏感性。这项研究获得的见解有助于设计杂草的生物防治计划，以及作物抗虫性的育种计划。

Plant defenses against herbivory can be divided into two types of traits. Some traits influence the likelihood that herbivores will settle on and consume the plant, and are called resistance. Other traits affect physiological adjustments to mitigate the adverse effects of damage, and are called tolerance. The effects of defense traits on plant fitness will not be static, but vary as herbivore population densities wax and wane. Theoretically, selection on plant defense can be analyzed as selection on reaction norms for the defensive components. To test this theory experiments to determine, (1) How the contributions of resistance and tolerance to plant fitness vary with herbivore density, and, (2) whether there are trade-offs between resistance and tolerance that vary with herbivore density are proposed. This investigation will use the native weed, goldenrod (Solidago altissima). Genotypic replicates will be planted in plots where herbivore population density or infestation levels are manipulated. The results will reveal the sensitivity of selection on defense components to herbivore population density. Insights gained in this study can help in designing biological control programs for weeds, and breeding programs for crop resistance to insects.