Plant species that vary in flower color are excellent models for understanding the evolutionary processes that maintain variation. However, the insects that are attracted to the flowers and subsequently pollinate them perceive color in the ultraviolet (UV) spectrum, and many plants have UV floral patterns (i.e., variation in the degree of UV reflectance) that go unseen by the naked human eye. The main hypothesis for the evolution of UV flower color is pollinator attraction and efficiency. However, factors like abiotic stress may also impose natural selection. Neither of these hypotheses has been adequately tested, thus we are far from a synthetic view of the evolutionary processes influencing floral patterns as they appear to insects. This project will address this gap using Potentilla, a plant genus highly variable for floral UV pattern, some species have patterned flowers while others are UV-absorptive or reflective. The research will examine the evolutionary relationships within the genus and characterize floral traits and habitat for all species to reveal evolutionary transitions in UV pattern. Further, field-based experiments will test putative biotic and abiotic drivers of UV pattern diversification.
Understanding the evolution of diversity of flower color is important to conservation of biodiversity. In addition, understanding plant pollinator interactions has important practical implications for agriculture. Genetic data on the plants will be made available through public databases. The project includes mentoring several undergraduates in the scientific process as well as graduate student training. The project will also include outreach through the University of Pittsburgh Middle School Outreach Program, including teacher training and classroom participation.
