Effects of 3-Trophic-Level Interactions on Sex Ratios of an Herbivore and Parasitoid

十字花科植物间的三营养级相互作用， 它们的主要食草动物之一，小菜蛾 小菜蛾及其主要寄生蜂岛屿弯顶蜂Diadegma insulare 研究了 蛾类的性比和种群数量， 寄生蜂与寄主植物的差异有关; 而营养水平很可能会对 种群规模的调节和相互作用的动态 这些昆虫物种和其他组成部分之间的关系 社区 草食动物性比的变化， 它的寄生虫，使用野生和栽培十字花科植物将是 探讨了 从野生和栽培品种中选择 栖息地将允许扫描大量的植物 属性，从个体差异等因素， 氮，防御化学和形态，直到人口 斑块大小和密度的变化。 的首要目标 一项研究旨在确定影响蛾和黄蜂性别的因素 在人口和社区范围内的比率。 次级 我们的目标是比较野生与栽培的这些相互作用 十字花科植物 总之，这些不同的系统涵盖了一系列 从高密度的社区情况，农业 在这样的环境中，人口的相互作用和性别比例 变异通常研究，以低密度，斑块状 这些相互作用和昆虫行为 可能进化了。

Three-trophic-level interactions among cruciferous plants, one of their major herbivores, the diamondback moth Pluetella xylostella and its major parasitoid Diadegma insulare will be studied. Sex ratios and population sizes of both the moth and the parasitoid are correlated with differences in food plants; and the trophic levels are likely to have major effects on the regulation of population size and the dynamics of interactions between these insect species and other components of the community. The variations in the sex ratios of the herbivore and its parasitoid, using both wild and cultivated crucifers will be explored. Selection of species from both wild and cultivated habitats will allow the scanning of a large array of plant properties, from individual variation in such factors as nitrogen, defensive chemistry and morphology, up to population variation in patch size and density. The primary goal of the research is to identify factors affecting both moth and wasp sex ratios within population and community contexts. The secondary goal is to compare these interactions on wild vs. cultivated crucifers. Together, these different systems cover an array of community situations from the high density, agricultural environments in which population interactions and sex ratio variation are usually studied, to the low density, patchy communities in which these interactions and insect behaviors probably evolved.