The evolution of prey choice in bee wolf wasps and their relatives (Crabronidae: Philanthinae): First insights from a preliminary molecular phylogeny

To fully understand why an animal behaves a certain way, researchers must simultaneously address four different aspects of behavioral causation: what Tinbergen famously called the physiological, survival value, ontogenetic, and evolutionary/phylogenetic origins of behavior. While the colorful and charismatic digger wasps of the subfamily Philanthinae (Hymnoptera: Apoidea: Crabronidae) have been the subjects of numerous classic behavioral studies, the vast majority of that work has focused exclusively on physiological- or Darwinian- (survival value) explanation; relatively little effort has gone into uncovering the deep phylogenetic history of the group's behavior or the homology of specific behaviors among taxa. Of particular interest here is the untold story of how an ancestral philanthine prey preference diversified into the varied prey preferences and hunting patterns that we see today. The current study presents a preliminary attempt to reconstruct that story using the first molecular phylogeny for the group. The results of parsimony and maximum likelihood phylogenetic analyses based on nucleotide sequence data from five loci (18S rDNA, 28S rDNA, RNA polymerase II, elongation factor-1 alpha, LW rhodopsin) are presented and their implications for prey choice evolution discussed.