9311273 Root The introduction of two closely related European chrysomelid beetles (Galerucella calmariensis and G. pusilla) by the U.S.D.A. for the biological control of purple loosestrife (Lythrum salicaria), and problem weed in wetlands, is a unique opportunity to study the population dynamics of ecological invasions. A third congeneric species, G. nympheae, is native to North America and feeds on purple loosestrife only in limited locations. The study uses a comparative approach to assess the factors affecting both local establishment and geographical spread of these three beetle populations. Differences in the probability of local establishment, both among species and for different numbers of insects released, will be determined using replicated releases in isolated locations. A separate, single, large release will be used to track the patterns of spread through a heterogeneous environment. %%% Invasion biology, the study of the establishment and spread of exotic species, is a field of growing interest and importance, particularly as the impact of humans in biological exchanges between regions has increased markedly. This project focuses on factors influencing the establishment and spread of exotic populations and their role in the biological control of pest species. *** S Courier (0N (s0p12h10 (0N (s0p12h10.0v0s0b3T , , % 2 0 _ R S 9311273 Root The introduction of two closely related European chrysomelid beetles (Galerucella calmariensi s and G. pusilla) B S G I ! ! ! ! F $ $ ( Times New Roman Symbol & Arial " h C E K e , P Doctoral Dissertation Elizabeth M. Behrens Elizabeth M. Behrens
