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

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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.