Hastings Natural History Reservation

11 May, 02 AM - 12 May, 11 AM

Integrated studies of mating-system evolution in a diverse group of self-compatible annuals (Collinsia and Tonella, tribe Collinsieae, Scrophulariaceae s.l.) are proposed to test major hypotheses concerning evolutionary lability of plant mating systems, including Stebbins? (1957) hypothesis that highly selfing lineages represent evolutionary dead-ends. Floral development, timing of self-pollination, outcrossing rate, and the role of pollinator failure in the evolution of autonomous selfing will be investigated within a phylogenetic framework to characterize mating systems throughout Collinsieae and to reconstruct the dynamic history of mating-system change in the tribe. Available developmental and phylogenetic evidence indicates repeated shifts between large-flowered (putatively highly outcrossing) and small-flowered (putatively highly selfing) conditions during evolution of Collinsieae, although the directions of these shifts cannot yet be unambiguously reconstructed. Although we cannot yet reconstruct unambiguously the directions of these mating-system shifts, our available data provisionally support multiple origins of outcrossing from selfing, in contrast to Stebbins? hypothesis. We anticipate sampling of additional populations and key species will strengthen support for acceptance or refutation of Stebbins? hypothesis. We propose to develop Collinsieae as a model system to test hypotheses about the role of reproductive assurance in, and the directionality of, plant mating-system evolution. We will also test for associations between traits, or covarying suites of traits, and predominantly outcrossing strategies (i.e., late or delayed selfing) and predominantly inbreeding strategies (i.e., early or prior selfing). Our combined experience in mating-system studies, flower development, pollination ecology, and phylogenetic and comparative analyses will allow us to combine approaches of post-anthesis flower development, pollination biology, molecular phylogenetics, and genetic estimates of plant mating systems to achieve an unusually detailed and synthetic view of the evolutionary dynamics of this promising study group. Generation of robust phylogenetic data, based on extensive sampling of taxa and molecular characters, and rigorous characterization of mating systems and post-anthesis floral development throughout Collinsieae will allow mapping of components of mating systems for inference of evolutionary history and phylogenetically corrected statistical analysis of trait covariation. With this new information we can ask evolutionary questions of broad scientific importance, e.g., (1) Does a strongly selfing strategy constitute an evolutionary "dead end," as widely assumed? (2) Does the reproductiveassurance hypothesis explain mating system evolution? (3) Is timing of self-pollination a good predictor of outcrossing rate? (4) Has homoplasy in mating-system shifts involved changes in similar suites of morphological and developmental traits? Our proposed research will have the broader impacts of enriching graduate and undergraduate education at our three institutions by the development of intellectual connections among our complementary research programs and involving students in unusually integrative evolutionary studies. Three graduate students and multiple undergraduates will be enlisted in our efforts and will participate in analytical and experimental studies spanning several sub-disciplines of evolutionary biology, conducted in the field, laboratory, and greenhouse; graduate students will also participate in exchanges among PI labs. Their involvement in the proposed investigations will provide them with training and exposure to a wider diversity of approaches than would be possible in a single laboratory and will place them in a strong position to develop creative, crossdisciplinary scientific careers.

Visit #5323 @Hastings Natural History Reservation

Approved

Under Project # 4223 | Research

Unravelling the dynamics of mating systems evolution n the tribe Collinsieae

graduate_student - University of Pittsburgh

Reservation Members(s)

Group of 2 Graduate Student May 11 - 12, 2004 (2 days)

Reserve Resources(s) | Create Invoice

Ranch House 2 May 11 - 12, 2004