Sexual dimorphism and sexual allocation in flowering plants: a synthesis of data (Visiting Scholar)
Part 1: Sexual dimorphism of mating traits seems weaker in flowering plants than in animals, and more frequently involves greater exaggeration of female rather than male traits. Is there something different about sexual selection and the evolution of dimorphism in plants? To find out, I will create a database of dicliny (separate-sex flowers) and floral sexual dimorphism among angiosperm taxa, along with basic plant habit and biogeographic data, mapped onto the angiosperm phylogeny. Analysis of these data will reveal any phylogenetic patterns in the evolution of floral dimorphism and will open a window on plant-specific aspects of mating that affect sexual selection. Part 2: Sexual allocation theory for hermaphroditic flowering plants has a strong foundation and abundant empirical support, but there is a missing half to the story. The overwhelming focus of research attention has been on shifts in allocation among populations or species in response to changes in selfing or fitness gains in relation to resource investment. The missing half is the question of whether equal male-female allocation is, as expected, the “default” for the angiosperm life cycle given its special features of the alternation of generations. I will collate and re-analyze data from published studies to extract information on the location of “baseline” sexual allocation and of any shifts along the continuum of sex allocation in flowering plants. This analysis will assess the adequacy of current theory.