Ecological Effects of Global Change: Tree-Insect Interactions

9306981 Lindroth大气CO2浓度的增加和随之而来的气候变化预计将对森林生态系统产生重大影响。你对这些变化将如何影响生态相互作用的理解，尤其是树木和以树为食的昆虫之间的相互作用，充其量是初步的。二氧化碳浓度升高可以显著改变落叶乔木的叶化学，包括氮的减少和碳水化合物和碳基次生代谢物的增加。这些变化改变了食叶鳞翅目的表现。二氧化碳与其他环境工厂（养分有效性、落叶）相互作用，并可能与植物基因型相互作用，影响叶片化学和昆虫性能。本研究探讨了CO2升高、资源可利用性和植物基因型对树-草食-寄生性相互作用的直接和交互影响。实验系统包括颤杨、红橡树和糖枫（它们表现出一系列固有的生长速度和遮荫耐受性）、两种食叶昆虫（舞毒蛾和森林帐篷毛虫）和一种舞毒蛾幼虫寄生类（Cotesia melanoscelus）。碳-营养平衡理论为三个主要目标关联假说的发展提供了一个框架。这些目标是确定二氧化碳浓度升高、干旱胁迫、光照利用率和杨树基因型对树木化学成分的影响，以及对植食性昆虫和寄生蜂黑僵木生产性能的影响。许多研究人员和研究机构已经确定，对植物和食草动物相互作用的研究对于理解全球变化的生态后果至关重要。这项研究将有助于解决这一需求。本研究的特点包括强调二氧化碳与环境系统的相互作用，以及利用在生态和经济上都是北美落叶林中重要组成部分的树木和昆虫物种。

9306981 Lindroth Increasing concentrations of atmospheric CO2 and attendant climate change are expected to have significant impacts on forest ecosystems. You understanding of how these changes will affect ecological interactions, especially those between trees and tree-feeding insects, is at best rudimentary. Elevated CO2 can markedly alter the foliar chemistry of deciduous trees, including reductions in nitrogen and increases in carbohydrates and carbon-based secondary metabolites. These changes alter the performance of leaf-feeding Lepidoptera. CO2 interacts with other environmental factories (nutrient availability, defoliation) and possibly with plant genotype affect leaf chemistry and insect performance. This research investigates the direct and interactive effects of elevated CO2, resource availability and plant genotype on tree-herbivore-parasitoid interacations. The experimental system includes quaking aspen, red oak and sugar maple (which exhibit a range of inherent growth rates and shade tolorances), two leaf-feeding insects (gypsy moth and forest tent caterpillar) and a gypsy moth larval parasitioid (Cotesia melanoscelus). Carbon-nutrient balance theory provides a framework for development of three major goal associate hypotheses. These goals are to determine effects of elevated CO2 and 1) drought stress, 2) light availability, and 3) aspen genotype on tree chemical composition, and consequences for performance of insect herbivores and the parasitoid C. melanoscelus. %%% Numerous researchers and research agencies have identified studies on interactions of plants and herbivores as pivotal in understanding the ecological consequences of global change. This research will help address that need. Special features of this research include an emphasis on interactive effects of CO2 and environmental system, and use of tree and insect species that are ecologically and economically important components of North American deciduous forests.