| The Hawaiian Islands are home to approximately one quarter of the members of the family Drosophilidae. Despite the fact that these flies have been the subject of intense scientific inquiry for over forty years, the phylogenetic relationships in the group remain unsettled. With the exception of one large group, the picture wing flies, relationships among species groups, subgroups, and individual species are virtually unknown. Using five different data sets, comprised of both nuclear and mitochondrial DNA, I erect a hypothesis of phylogenetic relationships within the group and use it to address a number of relevant evolutionary and taxonomic issues.; In Chapter one I address higher level relationships. Fifty-seven species representing seven species groups of Hawaiian Drosophila are included in the analysis. For the first time in a cladistic analysis, members of the nudidrosophila and ciliated tarsus species groups are included. The results are largely in agreement with those of previous studies although two assemblages of species previously thought to be monophyletic are actually paraphyletic groups.; In the second chapter an additional forty-nine species are included in the analysis. The broader taxon sampling is used to address the question of whether the two major Hawaiian lineages, the members of subgenus Drosophila, and the genus Scaptomyza are sister to one another. Both continental and endemic Hawaiian representatives of genus Scaptomyza are included and the monophyly of this enigmatic group is evaluated. I also use the resulting phylogeny to examine the evolution of morphological and behavioral characters within each of the subgroups.; In the third chapter I confine my study to members of the planitibia species group of the picture wing flies. By comparing their biogeographic distribution with the phylogenetic relationships within the group it is possible to reconstruct the migratory history and estimate divergence dates within the group. This information is used to calibrate separate molecular clocks for both the mitochondrial (mt) and nuclear (nuc) DNA data. A Partitioned Bremer Support analysis is conducted and it is determined that evolutionary rates correlate with patterns of phylogenetic support. |
