Dissertation Research: Examining the Effects of Large Scale Migration on Local Population and Community Dynamics in Larval Odonates

大规模的迁移模式可以影响种群内部和种群之间大小结构的时空发生，但很少有研究明确地探讨这些模式如何影响同类相食和种群内捕食（IGP）等相互作用。蜻蜓Anax junius是一种迁徙的物种，经常在无鱼的池塘中扮演顶级捕食者的角色。这些特性使刺桐成为研究迁徙对种群规模结构和当地种群/群落动态影响的理想树种。我们概述了用刺桐和其他共发生的幼虫来评估这些效果的实验。第一节试验：a)大小变化对成对刺槐幼虫同类相食的影响以及刺槐群体内和群体间同类相食的可能性；b)大小结构和温度这两个季节性变量对刺桐幼虫自相残杀的影响。第二节测试了顶级捕食者种群大小结构对三种igp系统中中间捕食者和共享猎物生存的影响；b)密度介导的相互作用和性状介导的相互作用对三种IGP系统风险降低的相对贡献。

Large scale movement patterns can influence the spatio-temporal occurrence ofsize-structure within and between populations but few studies explicitly address howthese patterns affect interactions such as cannibalism and intraguild predation (IGP). Thedragonfly Anax junius is a species that migrates and often assumes the role of top-predator in fishless ponds. These attributes make A. junius an ideal species foraddressing the influence of migration on population size structure and localpopulation/community dynamics. We outline experiments with A. junius and other co-occurring odonate larvae evaluating these effects.Section I tests: a) the effects of size variation on cannibalism in paired A. juniuslarvae and the likelihood of cannibalism within and between cohorts of A. junius;and b) the effects of size-structure and temperature, two seasonally variablefactors, on cannibalism in populations of A. junius larvae.Section II tests the effects of population size-structure in a top predator (A. junius)on: a) the survival of intermediate predators and shared prey in a three speciesIGP system; and b) the relative contributions of density mediated interactions andtrait mediated interactions on risk reduction in a three species IGP system.