The Effects of Dispersal on the Population Dynamics and Parasitoid Diversity of a Multiparasitoid-Host System

9806635 Briggs理论研究预测，在竞争互动中，组成物种个体有限的扩散能力可以稳定消费者-资源互动，促进共存。然而，很少有经验证据支持这些理论预测，部分原因是在试图将现有的一般模型应用于特定系统时遇到了困难。研究人员将研究在一个自然宿主-多寄生性系统中传播的这些潜在影响，该系统涉及形成瘿的蠓，加州蠓及其寄生性物种群落。将讨论以下问题：(a)系统中寄主和拟寄生物有限的传播能力是否增强了寄主-多拟寄生物相互作用的稳定性？(b)不同的拟寄生物种之间的传播能力和竞争能力的差异是否促进了多个拟寄生物种在一个寄主物种上共存？(c) (a)和（或）(b)在什么空间尺度上发生？该研究将涉及为系统量身定制的空间显式模型的开发和参数化。该模型的预测将用于分析在自然种群中观察到的蠓丰度和寄生蜂多样性的模式，并将在不同空间尺度上操纵传播的现场实验中进行明确的测试。该项目的结果将对弥合理论和实验之间的差距作出重大贡献，以了解分散在种群调节和多物种共存中的作用。这项研究将对害虫的生物防治和濒危物种的保护具有直接意义。

9806635 Briggs Theoretical studies have predicted that limited dispersal abilities of individuals of the component species can stabilize consumer-resource interactions and promote coexistence in competitive interactions. However, there has been little empirical evidence to back up these theoretical predictions, in part because of the difficulties encountered when attempting to apply existing general models to particular systems. The investigators will examine these potential effects of dispersal in a natural host-multiparasitoid system involving the gall-forming midge, Rhopalomyia californica, and its community of parasitoid species. The following questions will be addressed: (a) Do limited dispersal abilities of the host and parasitoids in the system enhance the stability of the host-multiparasitoid interaction? (b) Do differences in dispersal ability and competitive ability between the different parasitoid species promote coexistence of multiple parasitoid species on the one host species? (c) At what spatial scale does (a) and/or (b) occur? The study will involve the development and parameterization of a spatially explicit model tailored to the system. The predictions of the model will be used to analyze the patterns of midge abundance and parasitoid diversity observed in natural populations, and will be tested explicitly in a field experiment in which dispersal will be manipulated at different spatial scales. The results of this project will make a substantial contribution towards bridging the gap between theory and experiments in understanding the roles of dispersal in population regulation and multispecies coexistence. This research will have direct implications for the biological control of insect pests, and for the conservation of endangered species.