Linking mechanisms of low temperature tolerance to species distribution

我的研究计划的长期目标是将环境胁迫耐受性的生理机制与物种范围和无脊椎动物种群增长联系起来。我目前的重点是低温生理学在设定极地范围限制中的作用。了解低温耐受性的生理和遗传限制对于预测气候变化下范围扩展的潜力至关重要。我建议以东部云杉芽虫的耐低温性作为研究这些联系的模型系统。该物种是原生森林害虫，在落基山脉以东的北美北方森林中经常发生景观规模的爆发。先前的研究已经确定，越冬温度是fumiferana种群规模的关键决定因素，并且由于气候变暖，其范围目前正在向北扩大。我将在三个研究主题中使用这个系统，从细胞生理学到物种分布，以更好地了解耐寒性在昆虫种群爆发和范围中的作用。在第一个主题中，我们将测试反复寒冷暴露后死亡的假设是由于在多个冷却和变暖循环中变性蛋白质在聚合体中的积累。我们将在幼虫切片上使用免疫组织化学来量化反复暴露后热休克和泛素标记蛋白的亚细胞定位。在第二个主题中，我的研究计划将使用一组由加拿大林业局（CFS）发起的新建立的C. fumiferana培养物，这些培养物来自从Inuvik到New Brunswick北部的9个种群，以量化低温耐受性变化的程度和机制基础。此外，我们将利用fumiferana的生活史来研究母体对耐寒性的潜在影响，并估计不同种群对耐寒性的局部适应。最后，在第三个主题中，我们将利用我们收集的关于低温耐受性变化机制和低温暴露对细胞的影响的数据来建立基于生理学的烟熏假丝酵母菌爆发模型。根据我们收集的表型可塑性和耐寒性能量成本的数据，以及航空调查数据，我们将能够测试在气候变化下允许耐寒性进化的混合模型。这三个主题将有助于将越冬生理学与物种分布联系起来，这种物种在加拿大具有重要的经济和生态意义。这将为低温生化适应的作用、低温生存中的热休克蛋白以及在快速变化的世界中适应新气候的进化潜力提供新的见解，同时为几名高素质人员提供尖端技术培训。

The long term goal of my research program is to link physiological mechanisms of environmental stress tolerance to species range and population growth in invertebrates. My current focus is on the role of low temperature physiology in setting poleward range limits. Understanding physiological and genetic constraints on low temperature tolerance is essential for predicting the potential of range expansions under climate change. I propose to use the low temperature tolerance of eastern spruce budworm Choristoneura fumiferana as a model system for investigating these links. This species is native forest pest with regular landscape-scale outbreaks in the North American boreal forest east of the Rockies. Previous efforts have identified that overwintering temperature is a key determinant of C. fumiferana population size, and its range is currently expanding northward due to climate warming. I will use this system in three research themes that link from cellular physiology to species distribution to better understand the role of cold tolerance in insect population outbreaks and range. In the first theme, we will test the hypothesis that mortality following repeated cold exposures is due to accumulation of denatured proteins in aggresomes over multiple cooling and warming cycles. We will use immunohistochemistry on larval slices to quantify subcellular localization of heat shock and ubiquitin-tagged proteins following repeated exposure. In the second theme, my research program will use a set of newly-established C. fumiferana cultures initiated by the Canadian Forest Service (CFS) from nine populations that range from Inuvik to northern New Brunswick to quantify the extent and mechanistic basis of variation in low temperature tolerance. In addition, we will leverage the life history of C. fumiferana to examine potential maternal effects on cold tolerance and estimate local adaptation of cold tolerance across populations. Finally, in the third theme we will use the data we have collected on mechanisms of variation in low temperature tolerance and cellular effects of low temperature exposure to produce physiologically-based models of C. fumiferana outbreaks. With the data we have gathered on phenotypic plasticity and energetic costs of cold tolerance, as well as aerial survey data, we will be able to test hybrid models that allow for evolution of cold tolerance under changing climate. These three themes will help link overwintering physiology to species distribution in a species that is both economically and ecologically important in Canada. This will provide novel insights into the role of biochemical adaptation to low temperature, heat shock proteins in low temperature survival, and evolutionary potential for adaptation to novel climates in a rapidly changing world, while providing training in cutting-edge techniques to several highly qualified personnel.