Plant Secondary Metabolites as Mediators of Trophic Interactions in a Tropical Forest Community

0074806Dyer量化和比较植物资源和消费者对生态群落的影响对陆地生态学家来说一直很困难，但它是理解自然和管理的生态系统如何结构以及它们如何应对扰动的重要组成部分。蚂蚁植物，胡椒cenocladum，及其相关的节肢动物一直是一个有用的系统，研究热带雨林中的自上而下和自下而上的操作的影响。拟议的实验将直接比较植物次生代谢物（酰胺）在调节草食动物与蚂蚁的作用的重要性。实验还将解决有关这些次级代谢物如何介导四个营养级之间相互作用的具体问题。将进行田间和荫棚实验来检验几个假设。捕食者和资源也将被操纵，植物化学，植物生物量，食草动物数量和上层营养水平的生物量的变化将被检查。将进行食草动物饲养实验，以进一步研究酰胺对食草动物的影响。这项研究是一个重要的一步，以获得一个清晰的了解在这个模型系统中观察到的营养级联。它将测试“绿色沙漠”模型，该模型表明植物次生化合物在塑造群落方面很重要，因为大多数植物对食草动物来说不是可用的资源。它还将阐明资源的可用性和植物化学在修改营养级联的作用。这项研究所解决的更大的问题是相关的资源可用性和化学防御，有关调节草食动物种群的因素的相对重要性的争议，并在蚂蚁植物互惠关系的研究进展目前的理论。研究结果将有助于对当前理论进行更好的评估，并更好地为保护生物学和生物控制领域的实际决策提供信息。

0074806DyerQuantifying and comparing the impacts of plant resources and consumers on ecological communities has been difficult for terrestrial ecologists, but it is an important component of understanding how natural and managed ecosystems are structured and how they respond to perturbations. The ant-plant, Piper cenocladum, and its associated arthropods have been a useful system for examining the effects of top-down and bottom-up manipulations in a tropical rain forest. The proposed experiments will directly compare the importance of plant secondary metabolites (amides) in regulating herbivory versus the role of ants. The experiments will also address specific questions about how these secondary metabolites mediate interactions between the four trophic levels. Field and shade house experiments will be conducted to test several hypotheses. Predators and resources will also be manipulated and changes in plant chemistry, plant biomass, herbivore numbers, and biomass of upper trophic levels will be examined. Herbivore feeding experiments will be conducted to further examine the effects of amides on herbivores. This research is an important step towards gaining an clear understanding of the trophic cascades observed in this model system. It will test the "green desert" model, which suggests that plant secondary compounds are important in shaping communities, because most plants are not usable resources for herbivores. It will also shed light on the roles of resource availability and plant chemistry in modifying trophic cascades. The larger questions addressed by this research are relevant to current theories about resource availability and chemical defense, controversies about the relative importance of factors that regulate herbivore populations, and advances in studies of ant-plant mutualisms. The results will allow an improved assessment of current theory and better inform practical decisions in the areas of conservation biology and biological control.