Stephanie Bartlett, Utah Valley University
Physical Sciences
Ephemeroptera, commonly referred to as mayflies, are found throughout the world. Within the order of Ephemeroptera resides a superfamily, Ephemeridea, commonly called burrowing mayflies. This common name was acquired due to certain physical and behavior characteristics present as nymphs. Ephemeridea nymphs live in the silt of aquatic environments and have adaptations for burrowing which include strong legs, as well as mandibular tusks. One exception to this is the family Behningiidae, which burrow, but lack the commonly associated mandibular tusks. Morphological data supported Behningiidae as sister to the other tusked burrowing mayflies, indicating that first burrowing behavior evolved and was later followed by the development of tusks(McCafferty; 1975 and 2004). While morphological data provides important insights into the evolution and phylogeny of mayflies, the development of molecular phylogenetics offers new contributions when determining evolutionary relationships within this superfamily. Objective: The purpose of this study is to investigate the relationships of the families of burrowing mayflies in order to test the hypothesis of tusk evolution. Methods: The specimens were acquired from collection efforts and colleagues. For each specimen the following laboratory procedures were carried out: DNA extraction, gene amplification via polymerase chain reaction, visualization via gel electrophoresis, and DNA sequencing. The genes targeted for sequencing included 12S mitochondrial rDNA, 16S mitochondrial rDNA, 18S nuclear rDNA, 28S nuclear rDNA, H3 nuclear protein coding, and CO1 mitochondrial protein coding. Data was also acquired from Genbank in order to augment missing data. Taxon sampling consisted of around 20 ingroup and 5outgroup taxa. Phylogenetic relationships were estimated using Maximum Parsimony, Maximum Likelihood, and Baysian methods. Conclusion: The families Behningiidae, Potamanthidae, Palingeniidae were supported as monophyletic. Behningiidae nested well within the other burrowing families. Hence, tusks evolved and were subsequently lost in the family Behningiidae even though it retained the burrowing lifestyle in the nymph.