Altered trophic interactions in a warming environment: insights into the population dynamics of eruptive herbivores

虽然气候变化对食草昆虫的直接和间接影响预计是可变和复杂的，但迄今为止最常见的记录结果是其分布的变化。阐明改变营养相互作用与分布变化和栖息地入侵的外来昆虫草食动物可以提供重要的见解基本生态过程。对于容易发生剧烈种群波动和大范围爆发的物种，比较新栖息地和原生栖息地的营养相互作用，可以确定影响其种群动态的关键因素，并量化塑造其进化的选择压力。 由于气候变暖的环境，山松甲虫（鞘翅目：小蠹科：小蠹亚科）经历了一个戏剧性的范围扩大到新的主机人口和物种占主导地位的地区。使用这种昆虫食草动物作为模型系统，拟议的研究旨在量化的营养相互作用和种群动态的爆发性森林昆虫在本地与最近入侵的森林。更具体地说，比较研究将量化的相对贡献（一）主机树防御，（二）种间竞争的相互作用，和（三）与天敌的相互作用，以代死亡率和动态的山松甲虫在本地lodgepole松（松contorta变种。宽叶松（Pinus latifolia）栖息地与新殖民的、进化上幼稚的黑松（lodgepole pine）、短叶松（Pinus banksiana）和黑松×短叶松杂交栖息地之间的差异。 山松甲虫最近的活动范围扩大，是北美本土爆发性食草动物入侵栖息地的第一个例子。使用6个相互关联的研究项目，将能够培训3名博士和3名硕士候选人，以及多达24名本科生（2篇理学士论文，12名现场助理，10名实验室助理），这项研究将为草食性昆虫种群的动态，昆虫-植物相互作用的演变以及爆发物种入侵栖息地的过程提供重要见解。

Although the direct and indirect influences of climate change on herbivorous insects are expected to be variable and complex, the most commonly documented result of warming to date has been shifts in their distribution. Elucidation of altered trophic interactions associated with distributional changes and habitat invasion by an alien insect herbivore can provide important insights into fundamental ecological processes. For species prone to dramatic population fluctuations and widespread outbreaks, comparisons of trophic interactions in novel and native habitats make it possible to identify key factors influencing their population dynamics, and quantify the selective pressures shaping their evolution.      As a consequence of a warming environment the mountain pine beetle (Coleoptera: Curculionidae: Scolytinae) has undergone a dramatic range expansion into regions dominated by novel host populations and species. Using this insect herbivore as a model system, the proposed research seeks to quantify the trophic interactions and population dynamics of an eruptive forest insect in native versus recently invaded forests. More specifically, comparative studies will quantify the relative contribution of (i) host-tree defenses, (ii) interspecific competitive interactions, and (iii) interactions with natural enemies to the generation mortality and dynamics of mountain pine beetle in native lodgepole pine (Pinus contorta var. latifolia) habitats versus newly colonized, and putatively evolutionarily naïve, lodgepole pine, jack pine (Pinus banksiana) and lodgepole x jack pine hybrid habitats.      The recent range expansion by the mountain pine beetle comprises the first example in North America of significant habitat invasion by an indigenous eruptive herbivore. Using 6 interrelated research projects that will enable the training of 3 PhD and 3 MSc candidates, and up to 24 undergraduates (2 BSc theses, 12 field assistants, 10 lab assistants), this research will provide critical insights into the dynamics of herbivorous insect populations, the evolution of insect-plant interactions, and the processes of habitat invasion by eruptive species.