Molecular Phylogenetics and a Time Scale for Diversification of the Higher Flies (Diptera: Eremoneura)

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DEB-0089745Brian M. WiegmannDrs. Brian Wiegmann and Jeffrey L. Thorne of North Carolina State University have been awarded a grant to study phylogenetic relationships of an economically important instect group. With nearly 60,000 described species, the Eremoneura, or higher-flies (Insecta: Diptera: Brachycera), are among the largest and most successful of Mesozoic-aged insect radiations. Conflicting morphological interpretations have fueled a debate over the relationships of the major subgroups within Eremoneura. The basal lineages of the two major eremoneuran groups, Empidoidea and Cyclorrhapha, have been particularly controversial. Despite recent attention, no molecular studies have yet addressed eremoneuran classification. This collaborative project will synthesize morphological and molecular evidence to reconstruct the timing and pattern of basal eremoneuran evolution. Recently proposed methods for estimating divergence times from nucleotide sequence data do not require the biologically implausible assumption that rates of molecular evolution are constant over time. Such methods for estimating divergence times are promising but have not yet received adequate evaluation or refinement. Eremoneuran relationships that are elucidated within this project, and recent compilations of fossil evidence will serve as a test system for the ability of new methods to estimate divergence times. Analyses will be carried out to: 1) test published hypotheses for the basal family-group relationships of Eremoneura, 2) test the monophyly of the Empidoidea and its position as proposed sister-group to the Cyclorrhapha, 3) reconstruct eremoneuran divergence times and test the robustness of divergence time estimation methods to differing genes and tree topologies, Molecular phylogenies and a reconstructed time scale for eremoneuran Diptera will be extremely valuable because Diptera are model systems for genetic, developmental, and evolutionary biology. Integration of molecular and morphological evidence on brachyceran phylogeny will ultimately provide a framework for uncovering patterns and causes associated with major Mesozoic-aged insect radiations.