Ecology of Invasive Forest Insects in the Boreal Forest: Role of Plant Resistance and Community Interactions

气候变化对生态系统有许多级联影响，近几十年来导致昆虫、鸟类和海洋物种范围的变化。物种范围的扩大是一种短期效应，可能会对新殖民生态系统的动态产生重大影响。在北美，山松甲虫(MPB)是一种非常令人担忧的物种扩张。目前在加拿大西部爆发的MPB已导致超过数百万公顷的松树死亡，构成已知的最大的邻接性森林昆虫疫情。现在，由于在北方和东部的松树上没有寄主相关的障碍，所以人们对其向东传播非常担忧。本研究的重点是研究松树的抗性以及本地生物与MPB的相互作用是否会影响MPB在杰克松森林中的入侵。我建议研究矮化寄生寄生在杰克松上是否会改变杰克松对MPB的抗性。寄生植物--矮生槲寄生是杰克松林中分布最广的树种应激源。槲寄生的感染进展缓慢，并随着时间的推移而加剧，导致树木活力下降，死亡概率增加。活力下降的树木可能为MPB的建立和存活提供机会。在我的实验中，我将进行一些田间和室内实验，以了解MPB和矮化槲寄生之间的相互作用，并使用成熟松树和幼年松树。我将重点介绍植物的化学防御，特别是萜类和酚类化合物，以评估影响松种间相互作用结果的防御机制，因为化学防御是针叶树抵御草食动物和真菌的重要机制。加深对MPB入侵将如何影响杰克松森林系统的理解将是该项目的重要贡献。这一认识对于阐明杰克松防治MPB系统的一般结构和行为具有重要意义，也将对发展杰克松森林MPB综合防治具有重要意义。

Climate change has many cascading impacts for ecosystems and in recent decades has led to shifts in the ranges of insect, bird, and marine species. Species range expansions are a short run effect that could have large impacts on the dynamics of newly colonized ecosystems. In North America, one species expansion of great concern is that of the mountain pine beetle (MPB). Current outbreaks of the MPB in western Canada have killed lodgepole pine trees over several million hectares, comprising the largest known contiguous forest insect epidemic. Now there is great concern about its eastward spread as there are no host-related impediments in boreal and eastern pines. My research focuses on whether jack pine tree resistance and interactions between native organisms and MPB affect the MPB invasion in the jack pine forest. I proposed to investigate whether dwarf mistletoe infection of jack pine trees alter jack pine resistance to MPB. Dwarf mistletoe, a parasitic plant, is the most wide spread tree stressor in the jack pine forest. Mistletoe infections slowly progress and intensify with time, resulting in reduced tree vigour and increased probability of mortality. Trees with reduced vigor might provide opportunities for MPB establishment and survival. I will conduct a number of field and indoor experiments to understand the interactions between MPB and dwarf mistletoe and use both mature and juvenile pine trees in my experiments. I will focus on plant chemical defenses, particularly terpenoids and phenolic compounds, to evaluate defense mechanisms that influence the outcome of interspecies interaction on jack pine because chemical defenses are important mechanisms for conifers against herbivores and fungi. Developing deeper understandings of how MPB invasion would affect the jack pine forest system will be important contribution of this project. Such understanding is important to elucidate the general structure and behavior of the jack pine system against MPB and will be critical for the development of the integrated pest management of MPB in the jack pine forest.