Ecological interactions affecting the evolutionof plant mating systems: Current research and future directions
Sakai, Ann , Weller, Stephen , Culley, Theresa , Campbell, Diane .
Blowing in the wind: selective factors in the evolution of sexual dimorphism in Schiedea.
Shifts in habitat may result in changes in available pollinators that influence evolution of mating systems and reproductive biology. The Hawaiian genus Schiedea (Caryophyllaceae) has radiated into a monophyletic lineage of 34 endemic species that occur in a variety of habitats with diverse breeding systems ranging from obligate self-fertilization to sexual dimorphism. Colonization of dry habitats with loss of insect pollinators and expression of inbreeding depression may have led to the evolution of sexual dimorphism with wind pollination in 10 Schiedea species. All sexually dimorphic species exhibit morphological traits typical of wind-pollinated species. The evolution of sexual dimorphism depends in part on the additive genetic variance-covarianice matrices within females, within males, and across the sexes. Both S. salicaria, a gynodioecious species with 13% females, and S. adamantis, a gynodioecious species with a higher frequency of females (39%) and more pronounced sexual dimorphism, exhibited additive genetic variation in almost all floral traits measured. Female allocation and floral size traits covaried more tightly than did those traits with allocation to stamens. The G-matrices of females and hermaphrodites differed, suggesting the potential for further independent evolution of the sexes. In S. salicaria, artificial selection for greater male biomass has led not only to greater stamen biomass but also a disproportionate gain in the number of pollen grains. Both ecological and evolutionary approaches have helped to elucidate patterns of change in breeding systems.
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1 - University Of California-Irvine, Department Of Ecology & Evolutionary Biology, 321 STEINHAUS HALL, IRVINE, CA, 92697-2525, USA
2 - University Of California Irvine, Department Of Ecology And Evolutionary Biology, 321 Steinhaus Hall, Irvine, CA, 92697, USA
3 - University Of Cincinnati, Department Of Biological Sciences, 614 Rieveschl Hall, Cincinnati, OH, 45221-0006, USA
Presentation Type: Symposium or Colloquium Presentation
Location: Delaware D/Hyatt
Date: Tuesday, July 10th, 2012
Time: 2:30 PM