Role of plant secondary compounds in invasion biology of an insect herbivore in novel habitats

杰克松是加拿大北方落叶林中的优势树种，为许多动植物物种提供基本服务。在其历史范围内，山松甲虫与樟子松有着长期的共同进化历史，并已适应利用其次生化合物。然而，目前尚不清楚杰克松和小叶松对甲虫的敏感性是否不同，因为这两个物种在次生化合物的组成方面存在差异，这些次生化合物可能会影响寄主树木与甲虫的相互作用。 在我的申请中，我提出了测试两组目标，目标是在杰克松森林中针对山松甲虫入侵动态的两个不同方面。研究1将综合短叶松对寄生植物病原菌、矮化槲寄生、山松甲虫及其共生真菌病原菌的生化和生理机制，以及它们与不同时间和空间尺度上的资源可获得性的关系。研究2将集中于山松甲虫在多个世代间产生的化学通讯信号(信息素)的变化，因为树皮甲虫在寄主树上产生信息素和聚集需要植物次生化合物。 从这些研究中获得的信息对于基本和应用理解山松甲虫在加拿大杰克松森林中的入侵动态和成功都是重要的。研究1将推进植物防御理论，同时增加对调节病原菌-食草动物关系和昆虫暴发的因素的了解。该项目还具有重要的应用意义：更好地了解影响树木寄主-病原体-昆虫相互作用结果的生理生化过程，可能会指导通过营林配方和遗传选择在最佳和次优环境中改善树木表现的策略。 研究2的结果将确定雄性和雌性山松甲虫是否能在新的寄主系统中保持化学交流。同样，树皮甲虫的攻击是否同步成功地定植并杀死了樟子松，对于确定山松甲虫在新生态系统中的暴发动态可能是重要的。从实用的角度来看，这些结果将有助于开发诱人的诱饵(诱饵)，以监测甚至控制新的杰克松林中的山松甲虫种群。

Jack pine is a dominant tree species in the Canadian boreal forest, providing essential services for a number of plant and animal species. However, its existence has been threatened by the invasive mountain pine beetle as it has killed millions of hectares of historical host trees, mainly lodgepole pine in Western North America during the last outbreak and recently invaded the western extend of jack pine forests in northern Alberta (Canada). Within its historical range, mountain pine beetle shares a long co-evolutionary history with lodgepole pine and has adapted to utilize its secondary compounds. However, it is unknown whether jack pine and lodgepole pine differ in their susceptibility to beetles as both species vary with respect to the composition of secondary compounds which could affect host tree-beetle interactions. In my application, I proposed to test two sets of objectives targeting two different aspects of mountain pine beetle invasion dynamics in the jack pine forests. Study 1 will integrate knowledge of biochemical and physiological mechanisms of jack pine resistance to a parasitic plant pathogen, dwarf mistletoe, and the mountain pine beetle and its symbiotic fungal pathogen and, in part, their relationship to the resource availability over different temporal and spatial scales. Study 2 will focus on the variation in chemical communication signals (pheromones) produced by the mountain pine beetle on jack pine across multiple generations as plant secondary compounds are required for pheromone production and aggregation by the bark beetles on the host trees. Information resulting from these studies will be important for both basic and applied understanding of mountain pine beetle invasion dynamics–and success–in the Canadian jack pine forests. Study 1 will advance plant defense theories while increasing understanding of factor regulating pathogen-herbivore relationships and insect outbreaks. This project also has important applied implications: Achieving a better understanding of the physiological and biochemical processes that influence the outcome of tree host-pathogen-insect interactions may guide strategies to improve tree performance in optimal and suboptimal environments through silvicultural prescription and genetic selection. Results of the study 2 will determine whether male and female mountain pine beetles can maintain chemical communication in the novel host system. Likewise, whether bark beetle attacks are synchronized to successfully colonize and kill jack pine trees could be important to determine the outbreak dynamics of the mountain pine beetle in the novel ecosystem. From a practical perspective, these results would be useful for the development of attractive baits (lures) to monitor and even control mountain pine beetle populations in the novel jack pine forests.