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

将研究十字花科植物的主要食草动物之一小菜蛾小菜蛾与其主要寄生蜂Diades ma inare之间的三个营养水平的相互作用。蛾和寄生蜂的性别比例和种群大小与食用植物的差异有关；营养水平可能对种群大小的调节和这些昆虫物种与群落其他组成部分之间的相互作用的动态产生重大影响。本课程将探讨野生和栽培十字花科植物中食草动物及其寄生蜂的性别比例的变化。从野生和栽培生境中选择物种将允许扫描大量的植物特性，从氮、防御化学和形态等因素的个体差异，到斑块大小和密度的种群差异。这项研究的主要目标是确定在种群和社区环境中影响蛾类和黄蜂性别比例的因素。第二个目标是比较野生十字花科植物和栽培十字花科植物之间的相互作用。总而言之，这些不同的系统涵盖了一系列群落情况，从通常研究种群相互作用和性别比变化的高密度农业环境，到这些相互作用和昆虫行为可能进化的低密度、零散的群落。

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.