Structure of Plant-Arthropod Associations: Impact of Herbivores on Community Composition and Host Performance

将研究在演替过程中，取食一枝黄花的昆虫对个体茎的生长和繁殖以及对田间群落组成的影响。在新清理的土地上，将抑制昆虫种群，以确定昆虫取食是否会影响哪些植物物种在这些地块中建立。为了补充这种整体的方法，更详细的实验将进行两个成员的老领域的社区，黄花和草莓，以评估草食动物在调解两者之间的竞争结果中发挥的作用。第二个目标是详细研究不同类型的草食动物喂养损害的影响，个别的一枝黄花茎的健身。以各种方式模拟食草动物损害的实验将允许调查昆虫损害如何破坏植物内碳水化合物源和汇之间的平衡。此外，由于生长在不同肥力水平的一枝黄花会吸引不同的食草动物，因此将进行实验以评估土壤肥力和昆虫取食方式对植物适合度的综合影响。将继续对以一枝黄花为食的几种昆虫种群的空间和时间变化进行长期研究。为了进一步了解动物群的结构和草食动物负载的质量在我们的各个站点，旨在确定几种昆虫的宿主发现能力的实验将进行。这些数据提供了一个背景下，通过允许我们的实验条件自然发生的频率来解释更集中的实验。它们也构成了关于黄花菜昆虫区系结构和物种间相互作用的新假设的基础。

The impact of goldenrod-feeding insects on the growth and reproduction of individual stems and on field community composition during the course of succession will be studied. Insect populations will be surpressed in plots of newly cleared ground to determine whether feeding by insects affects which plant species become established in these plots. To supplement this holistic approach, more detailed experiments will be performed on two members of the old field community, goldenrod and strawberry, to assess the role herbivores play in mediating the competitive outcome between the two. A second objective is to examine in detail the effect of different types of herbivore feeding damage on the fitness of individual goldenrod stems. Experiments in which herbivore damage is simulated in various ways will allow the investigation of how insect damage disrupts the balance between carbohydrate sources and sinks within the plant. In addition, because different herbivores are attracted to goldenrods growing at different fertility levels, experiments will be conducted to assess the combined effect of soil fertility and insect feeding style on plant fitness. Long-term studies of the spatial and temporal variation in the populations of several insect species that feed on goldenrod will be continued. To gain further insight into the structure of the fauna and the quality of the herbivore load at our various sites, experiments designed to determine the host finding abilities of several insect species will be conducted. These data provide a context for interpreting the more focused experiments by allowing the frequency with which our experimental conditions occur naturally to be determined. They also form the basis for building new hypotheses about the structure of the insect fauna of goldenrods and the interactions between species.