Studies on floral color evolution in the visible light spectrum have demonstrated floral color adaptations to pollinators, antagonists and abiotic conditions. It is well known that insects discern between areas of UV reflectance and absorbance on flowers. Thus, understanding the biological function of floral UV traits is essential towards gaining a holistic understanding of floral evolution. For instance, the phylogenetically widespread UV floral phenotype of petal bases absorbing UV and petal apices reflecting UV (‘bull’s eye’) is often thought of as a pollinator attractant but may also function in protection from harsh abiotic conditions. Moreover, the influence of UV phenotype on fitness is not understood.
I use a combination of UV photography, and experiments in the field and greenhouse to i) understand the degree of intraspecific variation in floral UV traits, ii) test the putative selective factors acting on UV traits and iii) elucidate upon macroevolutionary trends of floral UV patterns. I use the widespread perennial herb, Argentina anserina (formerly Potentilla), to address questions regarding phenotypic variation and selection: To what degree does the relative area of UV absorption vary? What is the genetic contribution to variation? Do pollinators select certain UV phenotypes? Does greater UV absorptive area increase pollen viability under harsh ambient UV conditions? Finally, I plan to use the genus Potentilla to address macroevolutionary questions: Does the bull’s eye pattern arise multiple times over evolutionary history? Do certain character states aggregate in species that inhabit similar regions/habitats?