DISSERTATION RESEARCH: Examining conflicting selection pressures on floral morphology of Silene stellata by the pollinating seed predator Hadena ectypa

University Of Maryland, College Park, College Park MD

Investigators

Abstract

Animal pollinators are thought to produce conflicting selective pressures on different structures within the flowers they pollinate. This study will investigate the differing selection pressures on stamens and pistils within flowers of Silene stellata, a native perennial herb, by Hadena ectypa, a nocturnal moth that acts as a pollinator as well as a seed predator of Silene. This is a pioneering study into the largely unexplored area of conflicting selective pressures on different aspects of floral morphology within a hermaphroditic plant species and will provide valuable insights into the evolution of floral diversity. In addition, this project will test and optimize the application of a genetic technique to estimate reproductive success of the pollen donor. The project provides excellent training opportunities for the graduate student and will also involve several undergraduate research assistants and high school interns in all of molecular biology and genetic aspects. This research will build on two successive years of field experiments to investigate phenotypic selection on stamens and pistils in flowers of Silene stellata, This project will develop and employ 24 highly variable microsatellite genetic markers to assess reproductive success of the pollen donor within 2138 seedlings germinated from a population of 231 tagged adult individuals. Success of the pollen donor will then be estimated by determining the multi-locus genotypes of the seedlings and the adult plants. The high resolution genotyping required to determine the identity of the pollen donor within a tetraploid such as Silene stellata necessitates the development of additional genetic markers. These new markers will facilitate future genetic studies of Silene stellata and will provide a model approach for other researchers investigating the genetics of poorly known, polyploidy species.