RICE, Amber M. *; PFENNIG, David W.; University of North Carolina-Chapel Hill; University of North Carolina-Chapel Hill: A Phylogeographic Investigation of Character Divergence

When closely related species co-occur, they often exhibit greater differences in morphology and resource use than do allopatric populations of the same species. Spadefoot toads (Spea bombifrons, S. multiplicata) exhibit such divergence in tadpole morph production and foraging behavior. Earlier studies suggested that selection to minimize resource competition lead to divergence in morph production. Yet, it remains unclear whether such divergence resulted from selection in sympatry to reduce resource competition (i.e., character displacement), or whether it was a carryover of differences that arose in allopatry as lineages of each species adapted to different environmental conditions. We used a phylogeographic approach to distinguish between these possibilities.