Majetic, Cassie , Raguso, Robert A. , Ashman, Tia-Lynn .
Geographic patterns of floral scent-floral color association in Hesperis matronalis (Brassicaceae) and their implications on female fitness.
Floral color and floral scent have long been viewed as potential targets of pollinator-mediated selection. While the fitness effects of color have been well studied in many species, studies of floral scent focus on pollinator visitation or assumed pollination from floral morphology. Few studies directly examine the relationship between plant fitness and scent emission rate or composition, and those that do generally focus on the presence or absence of floral scent rather than traits such as scent emission rate or composition. In addition, trait associations may complicate relationships between scent and fitness. Floral anthocyanin content may be directly linked to one or more categories of floral scent volatiles, namely benzenoids and phenylpropanoids, as these compounds are all produced by the shikimic acid pathway. Thus, we might expect that volatile compounds sharing a production pathway with anthocyanins will show a strong association with floral color in a color polymorphic plant species regardless of population of origin. Scent compounds that do not share biochemical pathways with anthocyanins, such as terpenoids, might show more population-specific patterns of scent emission rate and/or composition. Using five populations of purple/white polymorphic Hesperis matronalis across a geographic range in North America, we explore whether scent association with color is specific to compounds that share a root biochemical pathway with anthocyanin production and whether population-specific patterns dominate floral scent composition and emission for other categories of scent volatiles. We then examine whether floral color and/or floral scent emission rate (by chemical category) or composition at dawn or dusk affects female fitness in four populations of H. matronalis. Examination of multiple populations during two time periods of scent emission provides a unique opportunity to evaluate the importance of scent emission timing on plant fitness and to determine if the fitness-scent-color patterns vary between populations.
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1 - University of Pittsburgh, Department of Biological Sciences, 222 Clapp Hall, 4249 Fifth Avenue, Pittsburgh, PA, 15260, USA
2 - University of South Carolina, Department of Biological Sciences, Coker Life Sciences Building, 700 Sumter St., Columbia, South Carolina, 29208, USA
3 - University of Pittsburgh, Department of Biological Sciences, Langley Hall, Pittsburgh, Pennsylvania, 15260, USA
Presentation Type: Poster:Posters for Sections
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM