DISSERTATION RESEARCH: Spatial Scale and Population Persistence: Insights from a Plant-Herbivore-Parasitoid System

962301 Frank这项研究的重点是种群如何在自然界中持续存在。 这一目标是通过两种方式实现的：（1）调查当地人口的动态，以确定可能稳定人口波动的因素，以及（2）在更广泛的空间尺度上进行调查，以确定当地人口之间的相互作用是否可以带来区域持久性。 本研究系统由丑角虫（Murgantia histrionica），一个草食动物的膀胱（Isomeris arborea），和两个寄生虫攻击错误的鸡蛋。 斑块状分布的寄主植物清楚地描绘了单位，当地和区域的动态将进行调查。 在当地规模上，拟寄生蜂排斥实验将进行，以确定是否存在两个异步作用的寄生蜂导致宿主种群稳定。 在区域范围内，主机和寄生虫的传播将被操纵在实验群岛，以确定当地人口之间的传播是否导致区域稳定。 扩散操作将通过检查扩散的距离和密度依赖效应，以及扩散和环境异质性之间的相互作用如何影响当地人群之间的相互作用的经验和理论探索来补充。 这项研究的结果将是重要的，原因有几个。 首先，有很多当前的兴趣在细分种群的动态，因为栖息地破碎化和保护的实际影响是相互关联的分散。 第二，研究系统的选择允许调查栖息地斑块如何影响物种之间的相互作用和社区水平的过程，影响植被。 在空间细分环境中的多物种相互作用也可以为昆虫害虫的生物控制提供见解。 了解复杂的物种相互作用如何在细分的栖息地中持续存在，可能是生物学科学中最重要的问题。

962301 Frank This research focuses on how populations persist in nature. This goal is pursued in two ways: (1) Investigations of dynamics within local populations to identify factors that may stabilize population fluctuations, and (2) investigations on a broader spatial scale to determine whether interactions among local populations can bring about regional persistence. This study system consists of the harlequin bug (Murgantia histrionica), a herbivore on bladderpod (Isomeris arborea), and two parasitoids that attack bug eggs. Patchy distribution of the host plant clearly delineates the units on which local and regional dynamics will be investigated. On the local scale, parasitoid exclusion experiments will be conducted to determine whether the presence of two asynchronously acting parasitoids leads to host population stability. On the regional scale, host and parasitoid dispersal will be manipulated in experimental archipelagoes to determine whether dispersal among local populations leads to regional stability. Dispersal manipulations will be complemented by examination of distance and density-dependent effects of dispersal, and by empirical and theoretical explorations of how interactions among dispersal and environmental heterogeneity influence asynchrony among local populations. The results of this study will be important for several reasons. First, there is much current interest in the dynamics of subdivided populations that are interconnected by dispersal because of the practical implications for habitat fragmentation and conservation. Second, the choice of study system allows investigations of how habitat patchiness influences the interactions among species and the community-level processes that affect extinctions. Multi-species interactions in a spatially subdivided setting can also provide insights into biological control of insect pests. Understanding how complex species interactions persist in subdivided habitats is perhaps the most important issue for the science of con servation biology.