Interaction between inbreeding and phenotypic plasticity: Mimulus guttatus as a model system for studying establishment and persistence in native and novel environments.
In the model system, Mimulus guttatus, we have examined how eight source populations that vary in both population size and ecological attributes from the native range within California vary in their expression of inbreeding depression and phenotypic plasticity on population founding and establishment success in both native and novel habitats. Secondly, we are quantifying how 3 generations of enforced selfing influences individual fitness and the expression of phenotypic plasticity in the greenhouse, native field environment and non-native habitat.
Emerging results from our data analyses to date include striking variation among all eight source population in their commitment to sexual reproduction in the native range and a switch in life history strategy towards a preference for vegetative/asexual reproduction in the non-native environments. Overall performance in native and non-native habitats is trait dependent and not necessarily predictable or associated with ancestral environmental and genetic variability or population size. In our empirical investigation of inbreeding and phenotypic plasticity we are observing genetic variation among morphological, life history and fitness traits for the expression of phenotypic plasticity. We are also detecting a large environmental role on the expression of inbreeding depression as well as phenotypic plasticity. To our knowledge, this is the first series of experiments simultaneously examining both genetic and ecological factors that influence phenotypic plasticity and ultimately colonizing ability in both native and novel habitats.
In M. guttatus we have detected clear evidence that serpentine soil conditions and water availability act together and had strong phenotypic effects, alone and in combination on many floral and plant traits. The traits may evolve independently from Ca/Mg ratios and water availability. Genetic variation for plasticity was detected at both the field-habitat type and family levels for half of the traits studied. Phenotypic plasticity and genetic variation for plasticity are more important than local adaptation in the success of these populations found across a variable landscape in northern California.
Relevant articles:
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Murren, C.J. and M.R. Dudash. 2012. Variation in inbreeding depression and plasticity across native and non-native field environments. Annals of Botany 109: 621–632.
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 Conservation Biology: Evolution in Action edited by S. C. Carroll and C. W. Fox., pp. 68-80, Oxford University Press, UK.
Murren, C. J., L. Douglass, A. Gibson, and M. R. Dudash. 2006. Individual and combined effects of Ca/Mg ratio and water on trait expression in Mimulus guttatus. Ecology 87: 2591-2606.
Dudash. M. R., C. J. Murren, and D. E. Carr. 2005. Using Mimulus as a model system to understand the role of inbreeding in conservation and ecological approaches. Annals of the Missouri Botanic Garden. 92(1): 36-51.