Evolution of elongation factor 1-alpha in insects and implications for early bee phylogeny

Elongation factor 1-alpha (EF1α) is one of the most commonly used genes in insect phylogenetics. This gene occurs as two paralogous copies in some insect orders, including Hymenoptera, Coleoptera, and Diptera. We reconstruct the evolutionary history of this gene to determine the number of duplication events within insects. Using data from both copies gathered from a comprehensive sampling of major bee lineages (Apoidea), we explore the utility of this gene in reconstructing the early history of bees. Analyses involving phylogenetics, intron presence/absence, and self-rooting with paralogous copies all corroborate recent arguments against Colletidae as sister to all other bees, and yield some support for Melittidae as sister to all other bees. Combined phylogenetic analysis of both copies also provides evidence in favor of Melittidae monophyly, currently a contentious issue in bee phylogenetics. Implications of these results to our interpretation of early bee pollination biology are discussed.