AUTHOR=Tai King-Chun , Shrestha Mani , Dyer Adrian G. , Yang En-Cheng , Wang Chun-Neng TITLE=Floral Color Diversity: How Are Signals Shaped by Elevational Gradient on the Tropical–Subtropical Mountainous Island of Taiwan? JOURNAL=Frontiers in Plant Science VOLUME=Volume 11 - 2020 YEAR=2020 URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2020.582784 DOI=10.3389/fpls.2020.582784 ISSN=1664-462X ABSTRACT=Pollinators with different vision are a key driver of flower coloration. Islands provide important insights into evolutionary processes, and previous work suggests islands may have restricted flower colours. Due to both species richness with high endemism in tropical-subtropical environments, and potentially changing pollinator distributions with altitude, we evaluated flower colour diversity across the mountainous island of Taiwan in a comparative framework to understand the cause of colour diversity. We sampled flower colour signaling on the tropical-subtropical island of Taiwan considering altitudes from sea level to 3300 m to inform how over-dispersion, random processes or clustering may influence flower signaling. We employed a model of bee colour space to plot loci from 727 species to enable direct comparisons to data sets from continental studies representing Northern and Southern Hemispheres, and also a continental mountain region. We observed that flower colour diversity was similar to flowers that exist in mainland continental studies, and also showed evidence that flowers predominantly had evolved colour signals that closely matched bee colour preferences. At high altitudes floras tend to be phylogenetically clustered rather than over-dispersed, and their floral colours exhibited weak phylogenetic signal which is consistent with character displacement that facilitated the co-existence of related species. Overall flower colour signaling on a tropical-subtropical island is mainly influenced by colour preferences of key bee pollinators, a pattern consistent with continental studies.