Differences in pollination success between local and foreign flower color phenotypes: a translocation experiment with Gentiana lutea (Gentianaceae)

Abstract

Background. The adaptive maintenance of flower color variation is frequently at-tributed to pollinators partly because they preferentially visit certain flower phenotypes.We tested whetherGentiana lutea—which shows a flower color variation (from orangeto yellow) in the Cantabrian Mountains range (north of Spain)—is locally adapted tothe pollinator community.Methods. We transplanted orange-flowering individuals to a population with yellow-flowering individuals and vice versa, in order to assess whether there is a pollinationadvantage in the local morph by comparing its visitation rate with the foreign morph.Results. Our reciprocal transplant experiment did not show clear local morphadvantage in overall visitation rate: local orange flowers received more visits thanforeign yellow flowers in the orange population, while both local and foreign flowersreceived the same visits in the yellow population; thus, there is no evidence of localadaptation inGentiana luteato the pollinator assemblage. However, some floral visitorgroups (such asBombus pratorum,B. soroensis ancaricusandB. lapidarius decipiens)consistently preferred the local morph to the foreign morph whereas others (such asBombus terrestris) consistently preferred the foreign morph.Discussion. We concluded that there is no evidence of local adaptation to the pollinatorcommunity in each of the twoG. luteapopulations studied. The consequences forlocal adaptation to pollinator onG. luteaflower color would depend on the variationalong the Cantabrian Mountains range in morph frequency and pollinator community composition.