A Phylogeny of Robber Flies (Diptera: Asilidae) at the Subfamilial Level: Molecular Evidence [PDF]

Robber flies (Diptera: Asilidae) comprise one of the largest groups of extant flies. Asilids constitute more than 500 genera and more than 5500 species with a worldwide distribution except Antarctica. Species range in size from less than one centimeter to nearly eight centimeters in length, and their prey consist of both small and large insects caught largely in flight. Asilid color patterns are simple: usually black, gray, or bronze, although some more colorful species appear to mimic bees and wasps.

The monophyly of Asilidae, including the problematic group Leptogastrinae (thread-waisted robber flies), is well-supported by synapomorphies including the fusion of the labella and prementum to form a heavily sclerotized, tube-like proboscis which contains the needle-like hypopharynx; the presence of a row or group of stout bristles along the lower edge of the face (mystax); and adult predatory behavior. Phylogenetic relationships of Asilidae with other families in Asiloidea have been recently investigated by molecular and morphological phylogenetic analyses. These analyses focused primarily on the monophyly of Asiloidea, a group including the families Asilidae, Apioceridae, Therevidae, Scenopinidae, Mydidae, Bombyliidae, and Apsilocephalidae.

Despite the considerable popularity of robber flies, and a rich history of extensive research on asilid morphology, taxonomy, and behavior, a comprehensive phylogenetic hypothesis for the subfamilies has yet to emerge.

We present the first formal analysis of phylogenetic relationships among the Asilidae, based on four genes: 16S rDNA, 18S rDNA, 28S rDNA and cytochrome oxidase II. Twenty-six ingroup taxa representing eleven of twelve described subfamilies were selected to produce a phylogenetic estimate of asilid subfamilial relationships via optimization alignment, parsimony, and maximum likelihood techniques. Phylogenetic analyses support the monophyly of Asilidae with Leptogastrinae as the most basal robber fly lineage. Apocleinae + (Asilinae + Ommatiinae) is supported as monophyletic. The laphriinae-group (Laphriinae + Laphystiinae) and the dasypogoninae-group (Dasypogoninae + Stenopogoninae + Stichopogoninae + Trigonomiminae) are paraphyletic. These results suggest that current subfamilial classification only partially reflects robber fly phylogeny, indicating the need for further phylogenetic investigation of this group.

Lab personnel involved in research:
Seth Bybee
Sean Taylor
Michael Whiting

Outside Collaborators:
Riley Nelson