WHO: Dana Dudle, Biology
WHERE: UB 231/232
WHEN: Tuesday, April 30 @ 11:30
Soapwort is Pink; Harebells are Blue: Studying Floral Color Variation on New Zealand Mountainsides and Indiana Roadsides
The persistence of variation in floral color within a single population of plants is a classic puzzle for plant reproductive biologists. Because flower color is strongly associated with pollinator attraction in many species, a common expectation is that a plant's pollinators will drive the evolution of flower color toward their own preferences. Explaining how different colors persist in a plant species raises interesting questions about correlated selection on associated plant traits, environmental effects on flower color and/or subtle preferences of pollinators. While on sabbatical last year, I studied variation in the floral color of two species: Wahlenbergia albomarginata (New Zealand harebell) and Saponaria offic diinalis (common soapwort, or bouncing bet). Wahlenbergia flowers are abundant on the slopes of the Southern Alps in New Zealand, and vary from bright white to pale blue. Though it is native to southwest Europe, Saponariagrows along roadsides and fields in the midwest. Individual flowers in this species change from white to pink as they age. In both of these studies, my collaborators and I described the extent and pattern of floral variation among native populations and studied pollinator preferences. We considered a variety of hypotheses that might explain the persistence of the floral color variation, including the influence of abiotic factors such as light environment, water availability and soil pH, and the possibility of selection for pigmented leaves that might indirectly influence the expression of color in flowers.