PHYLOGEOGRAPHY AND DIVERSIFICATION OF THE GREENISH BLUE BUTTERFLY (PLEBEJUS SAEPIOLUS) IN WESTERN NORTH AMERICA
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Investigation of an organism's biogeography is an important first step in understanding evolutionary processes. Often large-scale climatic or geographic events, like climate cycling of the Pleistocene, can influence dispersal patterns and create a disjunct and complex distribution in a species range. The Greenish Blue Butterfly, Plebejus saepiolus (Lycaenidae, Polyomattini), is a species which is widespread in North America, but populations are restricted to montane habitat. Here we use molecular genetic data and morphometric analyses of wing pattern variation to address the following questions (i) How has fragmentation and divergence occurred across populations based on current genetic variation in mitochondrial DNA based on phylogeographical hypotheses? (ii) How and where did colonization of populations in P. saepiolus occur across its geographic range? (iii) Does wing pattern variation parallel molecular differentiation, and agree with current subspecific designations within P. saepiolus? Overall, 31 unique haplotypes were identified in P. saepiolus with moderate isolation by distance, but no evidence of rapid expansion. Multiple phylogeographic models can characterize the complex genetic pattern in P. saepiolus. Genetic variation partitioned by mountain range with a few exceptions, however wing pattern variation does not parallel the genetic variation, and taxonomic designations should be revaluated.