Figure 2

Selection on flower colour and shape exerted by pollinators. Example of how discrimination on floral traits by pollinators can limit divergence away from a pollination syndrome through stabilising selection or promote divergence towards a new pollination syndrome. Distributions represent the frequency of phenotypic variation within syndromes and arrows show phenotypes selected against by pollinators. Bee pollinators select for a) yellow flower colour, open shape and small size, limiting divergence away from the bee-pollination syndrome. b) An increase in pollination by birds in part of the species range might promote divergence in floral traits by selecting for flowers with a greater proportion of red (preferred by birds and less attractive to bees), followed by c) selection for larger size and pendular orientation.