Behavioural ecology of interactions between trees and bark beetles mediated by climate

植食性昆虫与寄主植物之间的相互作用是陆地生态系统中最常见和最有效的相互作用之一。最近的一个例子是山松甲虫(MPB)的爆发，这是一种树皮甲虫，杀死了数亿棵成熟的松树。我的研究项目将在寄主树木动态栖息地质量的背景下，调查个体树皮甲虫的状态依赖繁殖策略。虽然长期以来人们观察到MPB在暴发期间主要杀死大直径的松树，但这种模式的原因尚未解决。理论预测，植物的防御分配将随生长速度和树高而非线性变化。利用荟萃分析和实证研究，我们将量化树木直径、高度、年龄和生长率(与工业相关的性状)与甲虫取食和繁殖的内树皮(韧皮部)的数量和质量之间的关系。我们的实证工作将集中在水分胁迫(空间和历史上)和松树树龄在MPB历史范围内和之外的影响，并考虑它们对MPB爆发的贡献。鉴于这些树木过程，我们将研究树木特性如何影响树种选择和树皮甲虫根据甲虫状态的繁殖策略。特别是，我们将测试MPB是否使用树的声发射来预测树抵御甲虫攻击的能力。为了研究MPB对大直径树木的明显偏好，我们将确定甲虫在不同直径的树木上的相遇几率和繁殖成功。利用我们对树体性状动力学和树皮甲虫状态相关繁殖行为的理解，我们将通过实证研究和模型来检验它们对甲虫种群动态的贡献。这项研究计划从行为生态学中带来了新的见解，以更好地了解树皮甲虫生态，这是影响加拿大森林的关键分类群。这项工作对于预测树皮甲虫和其他森林昆虫在气候变化中的影响至关重要。

Interactions between herbivorous insects and their host plants are among the most common and potent interactions in terrestrial ecosystems. A recent example is the outbreak of mountain pine beetles (MPB), Dendroctonus ponderosae, a bark beetle that has killed hundreds of millions of mature pine trees. My research program will investigate the state-dependent reproductive tactics of individual bark beetles in the context of the dynamic habitat quality of their host trees. While it has long been observed that MPB kill primarily large-diameter pines during outbreaks, the causes of this pattern are unresolved. Theory predicts that defence allocation by plants will vary non-linearly with growth rate and tree height. Using meta-analyses and empirical studies, we will quantify the relationships between tree diameter, height, age and growth rate (correlated traits of interest to industry) and the quantity and quality of inner bark (phloem) in which beetles feed and reproduce. Our empirical work will focus on the effects of water stress (spatially and historically) and tree age in pine within and outside the historical range of MPB and consider their contributions to MPB outbreaks. Given these tree processes, we will examine how tree traits influence tree choice and reproductive strategies of bark beetles according to beetle state. In particular, we will test whether MPB use tree acoustic emissions to predict the ability of the tree to defend itself against beetle attack. To examine the apparent preference of MPB for large diameter trees, we will determine encounter rates and reproductive success of beetles in trees that vary in diameter. Using our understanding of tree trait dynamics and state-dependent reproductive behaviour of bark beetles, we will test their contributions to beetle population dynamics with empirical studies and models. This research program brings new insights from behavioural ecology to better understand bark beetle ecology, a key taxon affecting Canada's forests. This work is critical for anticipating the effects of bark beetles and other forest insects in a changing climate.