Post Doctoral Researcher Tufts University Oakland, California
Ornamental flowering plants are often used in managed greenspaces to support pollinator populations. In natural systems, selection by pollinators is hypothesized to result in convergent multimodal floral phenotypes which are more attractive to specific pollinator taxa. In contrast, ornamental cultivars are bred via artificial selection by humans, and exhibit diverse and distinct phenotypes. Despite their prevalence in managed habitats, the impacts of artificial breeding on ornamental plant attractiveness to pollinator taxa is not well resolved. We used a combination of field and behavioral assays to evaluate how variation in floral visual, chemical, and nutritional traits impacted visitation by pollinator functional groups and bee species to 25 cultivars of five herbaceous perennial ornamental plant genera. We found that at the level of taxonomic group (bee, fly, butterfly, beetle), attraction was modulated by traits similar to those observed in co-selected communities. At the level of bee species, the relative influence of traits on visitation varied across plant genera. Some floral phenotypes led to a broadening of the visitor community while others excluded visitation by bee species. Overall, our results demonstrate the multimodal nature of floral signal on pollinator choice behavior and reveal how plant breeding may impact the attractiveness or accessibility of cultivars to pollinators.
