香梨园三种食心虫基于挥发物诱导的寄主选择行为及共存机制

Cydia pomonella, Euzophera pyriella and Grapholitha molesta are important fruit borers of fragrant pear orchard in South Xinjiang region, which have the latent threat to fragrant pear industry on account of some adaptable characteristics such as hidden habitat, boring damage, strong stress resistance to adversity and mixing co-occurrence on the same host plants. Chemical pesticides is frequent, but the control effect is low. It is particularly urgent and important to explore their new control approaches.In this study, Based on facts of significant intra- and inter-specific competition and coexistence relationship for three fruit borers, the mechanism of chemical information communication between three major fruit-boring herbivores and their same host plants and the role of herbivore induced plant volatile-mediated herbivore-herbivore intra- and inter-specific interactions are explored from the point of view of chemical ecology. For understanding the reaction mechanism of herbivore-induced fragrant pear volatiles in host plant orientation and selection of three herbivores, we take healthy, mechanically damaged host plants, and plants infested with larvae of the three fruit borers as research objects and obtain volatiles by using a dynamic headspace method. In order to make clear the ecological functions of fragrant pear volatiles, the volatile components are analyzed and identified by GC-MS, and the electroantennogram bioactivities and behavior responses of adults and larvae of three fruit borers to host Plant volatiles are tested by EAG or GC-EAD and "Y" tube olfactometry or wind tunnel, the active components are identified. On this basis, through the active components mixing and trap effect test in field, chemical compatibility of strong attracting or repelling effects are determined. The results of this research program are not only helpful to understand the host selection behavior and chemical-ecological mechanism of coexistence of multiple competition species of the same guild but also provide new pathways and innovative technologies of ecological regulation strategy on fruit borers in practice.

香梨园苹果蠹蛾、梨小食心虫与香梨优斑螟同域混合发生，均钻蛀隐蔽为害，抗逆性强，致使化学农药使用频繁而防效低下，已严重制约新疆特色香梨产业发展。本项目以三种食心虫为害香梨时既竞争又共存的生态关系为切入点，从化学生态学角度研究三种害虫与共同寄主间的化学信息联系及虫害诱导挥发物介导的种内种间互作机制。拟采用动态顶空集气法收集健康香梨、机械损伤香梨、分别被三种害虫取食后的香梨挥发物，用GC-MS技术分析其成分与含量，并比较不同处理香梨挥发物组分质和量的差异；进而通过EAG、GC-EAD、风洞等技术测定三种食心虫对香梨自然挥发物和虫害诱导挥发物的电生理和行为反应，明确活性组分，并将其复配后在田间进行生物活性测定，筛选具有高效引诱或驱避作用的化学配伍。该研究不仅有助于在理论上理解植食性昆虫的寄主选择行为和同资源种团内多个竞争物种共存的化学生态机理，且有助于在实践中发展害虫行为生态调控的新途径和新技术。

已有调查显示香梨园苹果蠹蛾、梨小食心虫与香梨优斑螟同域混合发生，在共同寄主香梨上存在生态位重叠但又共存发生，而竞争共存的适应机制仍不清楚。项目组成员利用昆虫化学生态学、行为生态学的原理与技术，通过寄主挥发物的提取、分析与活性测定，对寄主自然挥发物与虫害诱导挥发物在三种食心虫种内种间间隔分散与产卵选择中的作用进行了系统研究。首先明确了三种食心虫可在同一果园同域混合发生；利用“Y”嗅觉仪测定结果表明香梨优斑螟成虫香梨优斑螟、苹果蠹蛾和梨小食心虫对共同寄主果实及其挥发性物质均有显著的选择趋性，并可诱导成虫的产卵选择与定位，进一步的研究结果表明虫害诱导挥发物对三种食心虫的生物活性低于香梨自然挥发物。采用采用固相微萃取法（SPME）和静态顶空处理吸附法（SHS）结合气质联用 GC-MS 对挥发物组分的鉴定结果表明，香梨自然挥发物组分中以乙酸己酯、己酸甲酯等酯类物质为主，占43.20%；食心虫虫害诱导香梨挥发物组分鉴定获得E-β-法呢烯、Z-β-法呢烯、水杨酸甲酯等17种共有挥发性化学物质。进一步对化合物进行活性测定，表明三种食心虫反应较高的共有化合物中包含α-法尼烯、顺-3-己烯乙酸酯和乙酸己酯，有负选择作用的化合物有水杨酸甲酯、E-β-法呢烯。综上，本研究获得了解释有关香梨优斑螟、苹果蠹蛾和梨小食心虫同域混合发生过程中适应共存的部分结果，有助于理解植食性昆虫的寄主选择行为和同资源种团内多个竞争物种共存，为进一步筛选具有引诱或驱避活性作用化合物及其组合提供了基础。项目执行过程中完成学术论文及会议论文2篇、学术著作2部、获授权软件著作权3项、实用新型专利2项。