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

食草昆虫与其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，Dendroctonus ponderosae，一种树皮甲虫，杀死了数亿棵成熟的松树。我的研究计划将调查树皮甲虫个体在其寄主树的动态栖息地质量背景下的状态依赖繁殖策略。虽然长期以来一直观察到MPB在爆发期间主要杀死大直径松树，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率和树高呈非线性变化。通过meta分析和实证研究，我们将量化树的直径、高度、树龄和生长速度（工业感兴趣的相关性状）与甲虫喂养和繁殖的内树皮（韧皮部）的数量和质量之间的关系。我们的实证工作将侧重于水胁迫（空间和历史）和树龄对MPB历史范围内外松树的影响，并考虑它们对MPB爆发的贡献。鉴于这些树木生长过程，我们将根据甲虫状态研究树木性状如何影响树皮甲虫的树木选择和繁殖策略。特别是，我们将测试MPB是否使用树木的声发射来预测树木抵御甲虫攻击的能力。为了检验甲虫对大直径树木的明显偏好，我们将测定甲虫在不同直径树木中的相遇率和繁殖成功率。利用我们对树皮甲虫的树性状动态和状态依赖生殖行为的理解，我们将通过实证研究和模型来测试它们对甲虫种群动态的贡献。这个研究项目带来了行为生态学的新见解，以更好地了解树皮甲虫生态学，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.