The goals of this proposal are to evaluate the genetic consequences of a rapid range expansion and to assess micro- habitat specialization within a species of disease carrying mosquito. The Asian tiger mosquito, Aedes albopictus, is an important vector of dengue fever and is also able to transmit yellow fever and a variety of native North American arboviruses. Aedes albopictus was introduced into the United States in the vicinity of Houston, TX, in the mid- 1980's, and its distribution now extends from Florida to Illinois and Ohio. Comparing within- and between-population variability among ancestral (TX) and derived (FL, OH) populations will elucidate how genetic drift, migration, and selection at linked loci have distributed variability during the range expansion of this species in North America. In order to assess molecular variation, AFLP markers will be developed and used to characterize population structure throughout North America, and between tire breeding and tree-hole breeding populations. Genetic variation and differentiation of quantitative characters central to the rapid invasion and climatic adaptation of this species in North America will be examined, and used to investigate the extent to which variation and differentiation of AFLP markers accurately predicts variation and differentiation of quantitative characters.