The cosmopolitan genus  Scaptomyza, comprised of 272 species and an exquisitely preserved fossil, is a compelling lineage for detailed study. Two-thirds of the species occur in Hawaii, where they comprise one-third of the Hawaiian drosophilid radiation, yet Scaptomyza species are present on all continents except Antarctica. The Scaptomyza lineage is nested phylogenetically within the paraphyletic subgenus  Drosophila. Many  Scaptomyza species  exhibit remarkable ecological and morphological adaptations, and larvae  exhibit an exceptionally wide range of feeding habits. Thus, the lineage is a potential model for understanding the evolution of insect life histories. From a genomic perspective, Scaptomyza research benefits from the genetic tools of its Drosophila relatives; four species from this lineage are slated for genome sequencing, and will be important placeholders for the dissection of drosophilid genome evolution. However, the taxonomy of the genus is confused, posing a major impediment for ecological, functional and genomic studies. The overall goal of this proposal is to estimate a phylogenetic framework for  the genus  Scaptomyza to allow assessment of the evolutionary relationships within and between all Scaptomyza subgenera. This phylogeny will be used to estimate the biogeographic origins of this lineage, as well as the timing and origins of the evolution of diverse larval life histories and morphological innovations linked to these ecological adaptations. Guided by strong preliminary data, this objective will be accomplished through three aims: Aim 1. Create molecular phylogenies of all subgenera of Scaptomyza using multiple loci and multiple optimality criteria for phylogeny reconstruction and time-calibrate these using fossil and geologic evidence;  Aim 2. Use a comparative phylogenetic framework to identify the biogeographic origins of the genus and subgenera, test the hypothesis that the genus arose in Hawaii, and examine dispersal and vicariance scenarios throughout the range of Scaptomyza subgenera;  Aim 3. Identify origins of ecological and morphological innovations correlated with life-history evolution in Scaptomyza. The applicants have shown with preliminary data that their inter-disciplinary team will be able to produce a well-supported phylogenetic framework to test the above hypotheses. This research will augment our understanding of Drosophila evolution, but will also inform more widely applicable theories of ecological adaptation and island biogeography.