Population ecology of an endemic and an invasive species

种群动态的原因和结果是种群生态学家的研究领域。地方性物种和外来物种的种群动态常常不同，因为地方性物种的爆发是暂时的，而外来物种的爆发是持久的。北半球特有森林鳞翅目最显著的动态是种群周期。与这些人口周期有关的特征是；暴发之间的周期性为6至11年，人口在5至8年期间增加，然后迅速下降，没有持续低人口密度的时期，不同人口之间具有同动性。西部帐篷毛虫的动物流行病是一种病毒性疾病。我们建议研究关于帐篷毛虫种群动态的两个问题：暴发种群中病毒感染的严重程度是否与环境条件有关，以及种群在站点之间的同步性是环境决定的还是由于分散？我们将利用新开发的遗传标记来确定飞蛾在种群间的传播在多大程度上保持同步性，并利用野外实验、天气和种群记录来研究病毒性动物流行病。在没有天敌的情况下，引入的生物体经常保持暴发密度。为了对抗这些暴发，引入了外来控制剂。种群生态学家面临的挑战是确定生物防治剂和目标杂草的特性，使其能够在较低的平衡下进行控制。在建立了一种新的生物防治剂之后，最近在不列颠哥伦比亚省最严重的牧场杂草漫漫性knapweed的急剧下降促使我们问：“成功的生物防治需要多少昆虫？”在选择生物防治剂的种类和数量时，需要节约，以保证这种处理外来入侵害虫的宝贵工具的未来安全。我们将通过田间试验和观察来确定单一药剂是否能成功控制knapweed，并比较成功药剂与不成功药剂的特点。

The causes and consequences of population dynamics are the domain of population ecologists.  Population dynamics of endemic and exotic species often differ in that outbreaks of endemic populations are temporary while those of exotic species are persistent. the most striking dynamics of endemic forest Lepidoptera in the northern hemisphere are population cycles. Characteristics associated with these population cycles are; a periodicity of 6 to 11 years between outbreaks, population increase over 5 to 8 years and then a rapid decline, no period of persistent low population density, and synchronicity among separate populations. For western tent caterpillars epizootics of a viral disease occur in population outbreaks. We propose to study two questions about tent caterpillar population dynamics: Is severity of viral infection in outbreak populations related to environmental conditions, and is the synchronicity of populations among sites environmentally determined or due to dispersal?  We will use newly developed genetic markers to determine to what extent dispersal of moths among populations maintains synchronicity and field experiments and weather and population records to study viral epizootics.In the absence of natural enemies, introduced organisms frequently maintain outbreak densities.  To combat these outbreaks, exotic control agents are introduced. The challenge to population ecologists is to identify the characteristics of biocontrol agents and target weeds that allow control at a lower equilibrium.  The recent dramatic decline of diffuse knapweed, the most serious rangeland weed in British Columbia, following the establishment of a new biological control agent, prompts us to ask "How many insects are necessary for successful biological control?" Parsimony in choosing the types and numbers of biocontrol agents is required for the future safety of this valuable tool for dealing with invasive, exotic pests.  We will use field experiments and observations to determine if a single agent can successfully control knapweed and compare the characteristics of successful to unsuccessful agents.