Impacts of polyandry and mate limitation on female fecundity and the population dynamics of the aspen leaf miner

一些物种的种群数量可能在很长一段时间内保持在较低的数量，然后迅速上升到非常高的数量。当这些物种对人力资源造成破坏时，它们的种群“爆炸式增长”就成了一个实际问题。在种群非常小的时候，研究种群往往很困难，因为个体非常稀少，很难找到。然而，了解是什么让一个物种变得稀有，以及什么会使种群进入快速增长期，对于预测和控制多种疾病的爆发非常重要。这项研究探讨了杨树潜叶蛾数量急剧循环的可能原因，这是一种微小的飞蛾，通常很少见，但可能会暴发并对杨树造成广泛损害。特别是，研究人员将测试小种群中的雌性是否无法像大种群中的雌性那样频繁交配和产卵。如果得到证实，在小种群中交配成功率低可能对控制其他森林害虫和减缓入侵物种的传播至关重要。由于其高水平的一夫多妻制和持续的低和高种群阶段，以颤杨为食的杨树叶潜蝇为探索交配Allee效应对大规模种群波动的潜在人口影响提供了一个很好的系统。这个项目将使用实验和观察相结合的方法来解决寻找配偶的Allee效应和一夫多妻制是否有助于维持杨树叶潜伏者的低阶段。具体地说，它将采用：1)交配实验来检验多次交配是否会增加雌性的繁殖力，以及2)对不同密度的种群进行观察研究，以确定潜在的和已实现的一夫多妻制是否会随着种群密度的增加而增加。更好地理解将种群保持在低密度或将其释放到增长阶段的机制，将有助于预测疫情可能在何时何地发生。

Populations of some species can persist at low numbers for long periods of time and then quickly rise to very high numbers. When these species inflict damage on human resources, their population "explosions" become a practical concern. It is often difficult to study populations when they are very small because individuals are so rare and hard to find. Yet, understanding what keeps a species rare and what happens to shift populations into periods of rapid growth is important for predicting and controlling outbreaks of many kinds. This research examines possible reasons for dramatic cycles of abundance in the aspen leaf miner, a tiny species of moth that is usually rare but can outbreak and cause extensive damage to aspen trees. In particular, investigators will test whether females in small populations are unable to mate as often and lay as many eggs as females in large populations. If confirmed, low mating success in small populations may be important in controlling other forest pests and slowing the spread of invasive species. Due to its high level of polyandry and sustained low and high population phases, the aspen leaf miner (Phyllocnistis populiella) feeding on quaking aspen (Populus tremuloides) provides an excellent system for exploring potential demographic impacts of mate-finding Allee effects on large amplitude population fluctuations. This project will use a combination of experimental and observational approaches to address whether mate-finding Allee effects and polyandry contribute to sustaining low phases of the aspen leaf miner. Specifically it will employ: 1) mating experiments to examine whether multiple mating increases female fecundity, and 2) observational studies across populations with varying densities to address whether potential and realized polyandry increases with population density. A better understanding of the mechanisms keeping populations at low density or releasing them into growth phases will aid predictions of where and when outbreaks are likely to occur.