Ecological Effects of Global Change: Tree-Insect Interactions

9306981林德罗斯大气中二氧化碳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，特别是树木和以树木为食的昆虫之间的相互作用的理解充其量是基本的。二氧化碳浓度升高会显著改变落叶树木的叶化学成分，包括氮的减少、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昆虫的性能。二氧化碳与其他环境工厂(养分可获得性、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表现。本研究调查了二氧化碳浓度升高、资源可获得性和植物基因型对树木-食草动物-寄生蜂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颜色)、两种食叶昆虫(吉普赛蛾和森林帐篷毛虫)和一种吉普赛蛾幼虫寄生(黑腹小蜂)。碳-养分平衡理论为三大目标相关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和1)干旱胁迫，2)光可获得性，3)杨树基因对树木化学成分的影响，以及对昆虫食草性动物和寄生黑囊线虫性能的影响。许多研究人员和研究机构认为，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。这项研究将有助于满足这一需求。这项研究的特点包括强调二氧化碳和环境系统的相互影响，以及使用在生态和经济上对北美落叶林具有重要意义的树木和昆虫物种。

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.