Using DNA to better understand cryptic species complexes in the dung breeding Ravinia (Diptera: Sarcophagidae)

Members of the genus Ravinia are closely associated with man and have a direct impact on the environment with their role in vertebrate waste decomposition. Members of the genus Ravinia can be very numerous in North American institutional collections, often comprising ca. 25-33% of the total Sarcophagidae specimens. Using Bayesian and maximum likelihood analyses, we infer the first phylogeny of this genus using two mitochondrial genes, Cytochrome Oxidase I and Cytochrome Oxidase II. These results indicate that paraphyly is present throughout the genus Ravinia, which can cause problems in the molecular identification of these cryptic species. Particularly the species Ravinia floridensis/lherminieri and Ravinia anxia/querula which cannot be readily distinguished based upon mitochondrial DNA. Our results show two distinct groupings within the Nearctic members of Ravinia which correlate with the species groupings in the previously synonymized genera Chaetoravinia and Ravinia. The Ravinia phylogeny produced from this study will allow us to address the conflict between genetic lineages and morphological identifications and consider the role of gene flow and/or retained ancestral polymorphisms. Furthermore, this study highlights the need for incorporating multiple, unlinked nuclear loci in a coalescent-based framework to determine if there is ongoing gene flow between morphologically delineated “species.”