Pollination, biogeography and phylogeny of oceanic island bellflowers (Campanulaceae)

We studied the pollination biology of nine island Campanulaceae species: Azorina vidalii, Musschia aurea, M. wollastonii, Canarina canariensis, Campanula jacobaea, Nesocodon mauritianus, and three species of Heterochaenia. In addition, we compared C. canariensis to its two African mainland relatives C. eminii and C. abyssinica. We asked to what extent related species converge in their floral biology and pollination in related habitats, i.e. oceanic islands. Study islands were the Azores, Madeira, Canary Islands, Cape Verde, Mauritius, and Réunion. Information about phylogenetic relationships of these species and their relatives were gathered from atpB, matK, rbcL and trnL-F regions, building the most complete phylogeny of Campanulaceae to date. Six of the island bellflower species were bird-pollinated and two (A. vidalii and M. aurea) were lizard-pollinated. Insects also visited some of the species, and at least C. jacobaea had both insect- and self-pollination. Several morphological traits were interpreted as adaptations to bird and lizard pollination, e.g. all had a robust flower morphology and, in addition, bird-pollinated species were scentless, whereas lizard-pollinated species had a weak scent. These examples of vertebrate pollination evolved independently on each island or archipelago. We discuss if these pollination systems have an island or mainland origin and when they may have evolved, and finally, we attempt to reconstruct the pollinator-interaction history of each species.