Michele R. Dudash

BIOL 760 Graduate course in Plant Population Biology

HONR 289C History of Evolutionary Thought: BIOL CORE course in the Honors Program

College Park Scholars Colloquium in Life Sciences

Graduate Seminars in Conservation, Restoration, Plant Pollinator Interactions, Mating System Evolution 

My research interests are motivated by my curiosity of what factors contribute to plant population's persistence or demise over time. The research in my lab encompasses the evolution and maintenance of breeding systems, plant-pollinator interactions, and the demography of populations. In this framework, the basic research conducted in my lab has direct implications for conservation and restoration strategies of threatened and endangered species. I am interested in sponsoring graduate students in all aspects of plant population biology. The questions addressed in my research program often require field experiments, complimented by greenhouse and laboratory studies.

I am particularly interested in quantifying the selective forces responsible for the evolution and/or maintenance of a specific breeding system by a taxon. Many plants, unlike most animals, reproduce by both self-fertilization and outcrossing to other individuals in the local population. Plants have evolved numerous mechanisms to promote matings between individuals and inhibit self-fertilization. This is because many plants experience inbreeding depression following self-fertilization at one or more stages in their life cycle, that reduces overall fitness compared to an individual that results from a mating between two unrelated individuals.

I have documented the magnitude and the genetic basis of inbreeding depression in two rapid cycling, closely related Mimulus species. One species is primarily an outcrosser and the other is primarily a selfing species. Inbreeding depression may be due to partially deleterious recessive alleles and/or overdominance where heterozygotes are superior to either homozygote. A priori, theory predicts that the magnitude of inbreeding depression will be less in a selfing species compared to an outcrossing species because partially deleterious recessive alleles are more readily purged from a selfing population. We examined the genetic basis of inbreeding depression via two approaches; (1) a quantitative genetics breeding design for both taxa and (2) sequential generations of selfing and outcrossing in the outcrossing taxon to examine the extent of purging in the populations. Future research stemming from this project is to understand the genetic basis of the great variation among maternal lines in their expression of inbreeding depression and how they respond to different inbreeding regimes across varying environments.

I am also involved in a long-term collaborative project to investigate the role of the ruby-throated hummingbird in the evolution of floral morphology and flowering time in the wide-spread, North American endemic, red flowered Silene virginica. We are using a multi-faceted approach that incorporates yearly demographic monitoring, floral and whole plant manipulations, and reproductive enhancement treatments in this study. This research takes me each year to University of Virginia's field station, Mountain Lake Biological Station in Pembroke, VA.

• Reynolds, R. J., M. R. Dudash and C. B. Fenster. 2009. Multi-year study of multivariate linear and nonlinear phenotypic selection on floral traits of hummingbird-pollinated Silene virginica. Evolution In press.
• Burd, M., T-L Ashman, T.L., D.R. Campbell, M. R. Dudash, M. O. Johnston, T.M. Knight, S. J. Mazer, R. J. Mitchell, J. A. Steets, and J. Cc Vamosi, 2009. Ovule number per flower in a world of unpredictable pollination. American Journal of Botany 96:1159-1167
• R. J. Reynolds, M. J. Westbrook, A. S. Rohde, J. M. Cridland, C. B. Fenster, and M. R. Dudash. 2009. Pollinator specialization and Pollination Syndromes of three related North American Silene. Ecology 90: 2077-2087.
• Fenster, C. B. W. S. Armbruster and M.R. Dudash. 2009. Specialization of flowers: Is floral orientation an overlooked first step? New Phytologist 183: 502-506
• Murren, C. J., C. Chang, and M. R. Dudash. 2009. Patterns of selection of two North American native and non-native populations of Monkeyflower (Phyrmaceae). New Phytologist 183:691-701.
• Dudash, M. R. and C. J. Murren. 2008. The influence of breeding systems and mating systems on conservation genetics and conservation decisions. In Evolution in Action edited by S. C. Carroll and C. W. Fox., pp. 68-80, Oxford University Press, UK.
• Fenster, C. B., G. Cheely, M. R. Dudash and R. J. Reynolds. 2006. Nectar Reward and Advertisement in Hummingbird-Pollinated Silene virginica, (Caryophyllaceae). American Journal of Botany 93: 1800-1807.
• Murren, C. J., L. Douglass, A. Gibson, and M. R. Dudash. 2006. Individual and combined effects of serpentine and drought on trait expression in Mimulus guttatus. Ecology 87: 2591-2602.
• Kephart, S. R. J. Reynolds, M. Rutter, C. B. Fenster, and M. R. Dudash. 2006. Pollination and seed predation by moths on Silene and allied Caryophyllaceae: Evaluating a model system to study the evolution of mutualisms. New Phytologist 169: 667-680.
• Dudash. M. R., C. J. Murren, and D. E. Carr. 2005. Using Mimulus as a model system tounderstand the role of inbreeding in conservation and ecological approaches. Annals of the Missouri Botanic Garden. 92(1): 36-51.
• Knight, T. Tiffany M. Knight, J. A. Steets, J. C. Vamosi, S. J. Mazer, M. Burd, D. R. Campbell, M. R. Dudash, M. O. Johnston, R. J. Mitchell, and T-L. Ashman. 2005. Pollen Limitation of Plant Reproduction: Pattern and Process. Annual Review of Ecology, Evolution, and Systematics 36: 467-497.