Assistant Professor of Organismic and Evolutionary Biology
Harvard University, Department of OEB
The evolution of mate choice to avoid hybridization in plants
Abstract: Plants are sessile organisms, and yet they have evolved a variety of mechanisms to actively choose their mates. Selection against the production of unfit offspring favors the evolution of traits that prevent reproduction with suboptimal mates. My research determines how and why mate choice evolves to prevent hybridization between species. I investigate the benefits and costs of evolving traits to reject heterospecific mates using examples from two closely related Texas wildflowers that have overlapping geographic ranges and produce sterile hybrids. First, I demonstrate how divergence in floral traits alters pollinator behavior causing a significant reduction in hybridization. By combining field experiments, lab experiments, and molecular experiments I identify the behavioral mechanisms underlying mate choice and estimate the strength of selection driving floral evolution. Second, I investigate the evolution of pollen-pistil interactions resulting in post-mating rejection of heterospecific pollen. Many plant pistils can evaluate and reject both conspecific (self) and heterospecific pollen; I explore how the shared mechanisms of recognizing and rejecting these two types of pollen can constrain the evolution of mate choice in plants.