Grace Burgin Thesis Defense (Robin Hopkins, Advisor)

Title: Mate choice in Phlox wildflowers

Abstract: Mate choice determines when, where, and how reproduction occurs. The summed effect of these decisions across generations drives evolutionary trajectories and patterns diversity across biological scales. Inspired by these far-reaching impacts, I focus on two primary arenas where plant mate choice decisions occur: 1) organismal interactions between plants and their pollinators and 2) cellular interactions between reproductive structures within the flower (pollen and pistil). 

In Chapter 1, I quantify the pollination environment in the Texas wildflower, Phlox drummondii, and identify high pollinator specialization towards a single butterfly species. Building on this empirical work in Chapter 2, I generate a novel theoretical framework for the role of pollinators as agents of dispersal. In Chapter 3, I test the hypothesis of increased self-fertilization in P. cuspidata as an adaptation to avoid costly hybridization with its related congener, P. drummondii. In Chapters 4 and 5, I use quantitative and functional genetics to investigate the genetic basis of the self-incompatibility mechanism active in P. drummondii. I map the genetic basis of intraspecific variation in the self-pollen rejection response and identify a novel gene causing self-pollen recognition in Phlox wildflowers. Taken together, my work integrates broad experimental approaches to explore how mate choice mechanisms function across biological scales.

Committee: Robin Hopkins (Advisor),  Elena Kramer (Chair), Dan Hartl,  Boris Igić