This project studies plants with foul-smelling red flowers that bloom in early spring in the southeastern U.S.A. These plants are intriguing because they appear to be sending the same floral message to pollinators. This looks like a floral syndrome (where unrelated plants converge on a common appearance or odor to lure the same, specific pollinators) BUT something is amiss: these flowers attract as pollinators a guild of generalized insects that feed on decaying organic matter. Documenting blooming patterns, visitors, and floral characteristics in populations across three southeastern states will characterize this apparent syndrome. This project impacts undergraduates who will perform all stages of science for academic credit. Students will read relevant literature and design experiments, set out field plots, collect and analyze their data. The following spring, students will present their results at the Association for Southeastern Biologists? annual meeting and submit them for publication. This project initiates the Wine Guild Curriculum Partnership with the GSU Botanical Garden that will impact several thousand K-12 school children and their teachers. This outdoor curriculum provides hands-on experience with pollination biology. The children will run essentially the same experiments at the Botanical Garden that investigators run in the field, providing first-hand experience with the scientific process and a greater appreciation for this rich floral heritage.
My colleagues and I study plants with foul-smelling red flowers that bloom in early spring in the southeastern U.S.A. These plants are intriguing because they appear to be sending the same floral message to pollinators. This looks like a floral syndrome (where unrelated plants converge on a common appearance or odor to lure the same, specific pollinators) BUT something is amiss: these flowers attract a guild of generalized insects that feed on decaying organic matter, as pollinators. We have studied these plants at six field sites across the eastern US, including my own site in Western North Carolina, where the project has been pivotal in the education of eleven undergraduates and one graduate student. Together, we have used a variety of methods to study floral biology and pollination in two of the project’s key species, the shrub Calycanthus floridus and the spring wildflower Trillium cuneatum. We have learned that the flowers of Calycanthus floridus are visited mainly by small sap beetles that crawl inside the flowers, chew on flower parts, and carry pollen on their bodies between flowers. The beetles appear to be mostly attracted by the scent of the flowers; there is no evidence that the dark red color of the flowers plays a role in drawing pollinators. The flowers bloom in the early spring, when the forest canopy is open, and finish flowering as the canopy leafs out. Flowers require pollinators to carry pollen from flower to flower; they cannot self-fertilize. However, in the years we have studied the plants, very low proportion of flowers have successfully produced fruits and seeds. Trillium cuneatum, although sharing a similar color and odor with Calycanthus, draws a very different spectrum of flower visitors, in this case a broad, diverse array of insects dominated by small flies and gnats but including many other insect groups. We conducted experiments with artificial flowers of varying color and with or without a yeasty odor meant to mimic the flower scent, to determine which cues are attractive to this diverse insect community. Results are very variable, depending on the insect group, but generally the wine-red color is not particularly attractive, whereas flowers with yeasty odor were more likely to draw insect visitors than unscented flowers. These results are similar to what we saw in Calycanthus, where scent played the greatest role in attracting pollinators. We have documented blooming patterns, flower visitors, and floral characteristics in populations of these two species to be used in the wider collaborative project as we look across species to characterize this apparent floral syndrome. The significance of our results will largely come from this comparison as we bring the data from all sites and species together to determine whether there is a cohesive floral guild of plants with wine-red, stinky flowers. In 2009, co-PI Boyd designed and taught a highly successful research-based undergraduate course focused entirely on the project; students in the course were engaged in all aspects of research, including literature review, experimental design, field and laboratory investigations, data analysis, and communication through oral presentations and written papers. Boyd has also trained other undergraduates and a graduate student in lab and field techniques as they participated in the project. The graduate student completed her Masters thesis as part of this larger project as well.
