1. Floral and Pollinator Evolution in Light of a Near-complete Phylogeny for Polemoniaceae Jacob Landis a,b, Margarita Hernandez b,c, *, Douglas E. Soltis a,b, Pamela S. Soltis b a Department of Biology, b Florida Museum of Natural History, c College of Agriculture and Life Sciences, University of Florida *Presenting author The wide diversity of floral variation results in part from pollinator-mediated selection. Flowers are often characterized by a given suite of traits, historically coined pollinator syndromes, which are associated with certain types of pollinators. These traits can include characters such as flower size, color, and overall morphology. Although a correlation between certain floral characters and specific pollinators is still debated, it is clear that understanding morphological traits, such as flower color and size, and their association with pollinators will deepen our understanding of the biology of specific interactions and will ultimately contribute to a refined view of pollinator syndromes. Furthermore, a strong phylogenetic framework will provide a solid foundation on which to map floral characteristics and establish relationships between morphological adaptations and genetic mechanisms. Here we present a new phylogenetic analysis of Polemoniaceae, with samples from 92% of the nearly 400 species. Using this phylogeny, we evaluate the evolution of flower color and flower size in the context of known pollinators. Analyses suggest over 40 transitions in flower color, with both color gains and losses observed. Flower size (length and width) was measured from herbarium specimens, with several accessions used per taxon when available. Analyses were conducted using continuous data, as well as binning into discrete groups. Many transitions result, with overall flower size increasing and decreasing in certain genera. Further analyses are needed to investigate the role that flower size plays in attracting specific pollinators. This project lays the foundation for ongoing projects on the genetic mechanisms involved in the evolution of flower color and flower size in Polemoniaceae. Results: Pollinators Materials and Methods Sequences for 71% of the taxa sampled were obtained through GenBank. In addition, we sequenced ITS and trnL-trnF from additional taxa to generate information for the rest of the taxa in this study. The DNA was obtained through a CTAB procedure from herbarium samples acquired from various universities and herbaria across the United States and from the Royal Botanic Garden in Scotland. The Polemoniaceae contain approximately 377 species in 26 genera (Johnson et al. 2008). The center of diversity of these species is western North America, with many genera also extending into South America (Grant 1959). This group has been of historical interest to botanists due to the great diversity seen in flower color, flower size, and overall morphology between species. Pollinator studies across angiosperms have shown that flower traits and pollinators are correlated, although this view is not universally held. Results: Flower Size The phylogeny in figure 1 includes 429 taxa in Polemoniaceae with close to 92% of the species sampled for this project. In this tree, pollinators are mapped onto the phylogeny, depicting 24 transition events. The most numerous transition is from an autogamous flower to a bee-pollinated flower. In maximum likelihood reconstructions, there is a slight favorability for hummingbirds as the pollinator for the ancestor of the family. Figure 1 Figure 2 Figure 2 shows the flower color of the species, including those that show single colors and those that are polymorphic in nature. Reconstructions slightly favor a white ancestor, with 88 transitions leading to the current colors displayed today. The two most numerous transitions were from a blue/purple flower to white and from a blue/purple flower to pink. Figure 3 shows the diversity of flower colors present in Polemoniaceae. Further Analysis and Future Work Acknowledgments and References Figure 4 Figure 5 Future studies of Polemoniaceae will determine the ancestral character states of the family, including its flower color and reproduction method. Small-scale studies have provided the rates of transitions shown in figure 4. These rates provide insight as to how the family diversified from an outcrossing white flower to an outcrossing colored flower. Color transitions in flowers of Polemoniaceae are also complex. Linanthus and Leptosiphon have particularly frequent transitions. To continue this study, a strong species-level phylogeny must be constructed for these genera. Figure 5 shows a small-scale phylogeny for several species in these genera and the diversity of flower color. Figure 6 shows corolla length mapped onto the phylogeny of Polemoniaceae. The ancestor of the group appears to be a large flower, with North American diversification leading to smaller flowers. Figure 3 also shows the diversity of sizes in the family. Figure 6 Figure 7 Figure 8 Flower size may also be represented by the length- to-width ratio. For nearly 120 taxa, this ratio and the pollinator were evaluated. Figure 7 shows the average ratio values in flowers with similar pollinators. These data show a relationship between certain ratios and pollinator classes. Figure 8 shows pollinators mapped onto a scatter plot of flower length versus width. There is a general trend in the clustering of certain pollinators in a particular range of length and width. Further studies will also be done in this area consisting of more sophisticated statistical approaches, such as the inclusion of phylogenetic relationships. Fenster, C.B., W.S. Armbruster, P. Wilson et al. 2004. Pollination syndromes and floral specialization. Annual Review of Ecology, Evolution, and Systematics 35: 375-403. Grant, V. 1959. Natural history of the phlox family. Martinus Nijhoff, The Hague, The Netherlands. Maddison, W.P. and D.R. Maddison. 2011. Mesquite: a modular system for evolutionary analysis. Version 2.75. Johnson, L. A., L. M. Chan, T. L. Weese, L. D. Busby, and S. McMurry. 2008. Nuclear and cpDNA sequences combined provide strong inference of higher phylogenetic relationships in the phlox family (Polemoniaceae). Molecular Phylogenetics and Evolution 48:997-1012. Zufall, R.A. and M.D. Rausher. 2003. The genetic basis of a flower color polymorphism in the common morning glory (Ipomoea purpurea). Journal of Heredity 94:442-448. Thanks to Megan Galarza and Jacob Holland for help with molecular work, and to Kent Perkins, Craig Freeman, Carolyn Ferguson, and Jim Solomon for assistance in collecting material from herbaria. Figure 3 Background Results: Color