Semester

Summer

Date of Graduation

2011

Document Type

Dissertation

Degree Type

PhD

College

Eberly College of Arts and Sciences

Department

Biology

Committee Chair

Jeffrey D

Abstract

The superfamily Oestroidea includes approximately 9% (≈14,000 spp.) of the order Diptera. Many members of the superfamily are of medical, veterinary, agricultural, and forensic importance. Although Oestroidea has been the subject of much scientific scrutiny, the exact patterns of phylogenetic relationships among the key groups of the superfamily are unresolved and controversial. For a better understanding of oestroid evolutionary hypotheses, phylogenies of Oestroidea were reconstructed at several taxonomic levels using DNA sequence data. The specific aims were to determine the phylogeny of the 1) genus Chrysomya (Chrysomyinae); 2) subfamily Chrysomyinae (Calliphoridae); 3) family Oestridae (Oestroidea); and 4) family Calliphoridae (Oestroidea). Sequence data from both mitochondrial and nuclear genes from 99 representative species were analyzed using maximum parsimony (MP), maximum likelihood (ML) and Bayesian (BA) methods. Trees obtained from the different phylogenetic methods were almost identical. The status of family Calliphoridae (the blow flies) has for years been the central systematic problem of the superfamily. These results show that Calliphoridae is polyphyletic, with the phylogenetic position of Mesembrinellinae still uncertain but clearly outside the lineage that includes other Calliphoridae and some non-calliphorids, and Polleniinae is the sister group of the family Tachinidae. Strong support for a sister group relationship between Rhiniinae and traditional calliphorid subfamilies undermines a recent proposal to give Rhiniinae family status. The Chrysomya and Chrysomyinae phylogenies were well resolved and suitable for testing a number of existing evolutionary hypotheses. The Chrysomyinae colonization of the neotropics apparently involved a single ancestral species, and the traditional chrysomyinae tribal classification should be abandoned. Tuberculate larvae evolved twice within Chrysomya, and published hypotheses about the evolution of sex determination, eye morphology, and genome size within the genus appear to be incorrect. Efforts to resolve the relationships of the Oestroid families were largely inconclusive, although the monophyly of the superfamily was strongly supported.

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