基于外来恶性杂草紫茎泽兰入侵我国以来不断扩张的现状，围绕外来有害植物入侵后出现生长与防御间的资源再分配这一科学问题，本项目采用生物地理比较和生理生态技术方法，以原产地（墨西哥）和入侵地（中国）紫茎泽兰种群为对象，重点研究：（1）天敌昆虫（例如专食性天敌泽兰实蝇寄生和广食性天敌东方行军蚁取食）对原产地和入侵地紫茎泽兰抗虫物质含量和耐受性的影响；（2）专食性天敌寄生和广食性天敌昆虫取食胁迫对紫茎泽兰的抑制作用是否存在加性效应？研究结果将诠释紫茎泽兰响应专食性天敌寄生、广食性天敌取食胁迫的生理调控机制，阐明紫茎泽兰在入侵前后的能量分配与防御策略演化动态，从而在验证紫茎泽兰的入侵是否符合“天敌逃逸假说”和“增强竞争力进化假说”的同时，丰富和发展“防御转化假说”，最终为协调应用天敌昆虫防治紫茎泽兰提供科学依据。

Based on the current situation of the continuous expansion of a global serious invasive plant, Ageratina adenophora, and focused on the scientific issue that the resources reallocation between growth and defense after an exotic plant invaded into a new area; the proposed project will work on A. adenophora populaitons that from origin area (Mexico) and invaded area (China), with techniques and methods of biogeographical comparison and physiological ecology, try to answer the following three questions: (1) Influence of insect herbivory (such as the specialist herbivore Procecidochares utilis and the generalist herbivore Dorylus orientalis) on the component of insect resistance and plant tolerance between origin and invaded populations of A. adenophora; (2) Whether additive effects exist beteween specialist herbivore and generalist herbivore on A. adenophora performance inhibition, especially for the invaded populations? The research results are essential and criticle to explain how invaded A. adenophora response to the stresses of specialist herbivores, generalist herbivores and interspecific competition, and its physiological regulation mechanism. It helps to clearly interpret the dynamics of energy allocation and defense strategy evolution during the invading process of A. adenophora. These results will be helpful for further verification of whether the invasion mechanism of A. adenophora is in accordance with the "Enemy Release Hypothesis" (ERH) and the "Evolution of Increased Competitive Ability hypothesis" (EICA), and enrich and develop the “shifting defence hypothesis”(SDH), which provides the scientific basis for the coordination of natural enemies and ecological restoration by competitive replacement of A. adenophora.