From piccolos to tubas in Salpichroa: the concerted evolution of trumpet-flowered Andean nightshades

RAGUSO, R. A.; MORÉ, M.; COCUCCI, A. A.; IBAÑEZ, A. C.; BARBOZA G. E.

Groningen

Congreso; XVI Congress European Society for Evolutionary Biology; 2017

European Society for Evolutionary Biology

Concerted changes in flower phenotype within a plant lineage provide strong evidence for adaptive radiation mediated by pollinator agents.Salpichroa Miers (Solanaceae) is comprised of 22 species that show remarkable variation in floral phenotype, e.g. a ten-fold difference in floral tube length. Here we aim to determine whether inter-specific floral variation is associated with changes in pollination mode. To this end we reconstructed the phylogenetic relationships and quantified three floral traits relevant to pollination: morphology, fragrance and nectar features. We also identified pollinators in natural populations. The phylogenetic reconstruction recovered two major clades; one grouping short flowered species that occur at the extremes of the latitudinal range (Mexico and Argentina), and another grouping the intervening species. The latter includes hummingbird-pollinated species that clearly exhibit an ornithophilous syndrome, i.e. yellow odourless nectar-rich flowers with very long corolla tubes. A multivariate analysis, including floral traits and pollination mode, showed two major paraphyletic groups, one with the ornithophilous species, and another with the short-flowered insect-pollinated species. Ancestral reconstruction of floral traits and pollination mode suggests that ornithophily evolved recently. Our results suggest that floral diversification in the genus Salpichroa is concomitant with adaptation to different pollinators.