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 attributed to pollinators in part because they preferentially visit certain flower phenotypes. We test whether Gentiana lutea -which shows a flower color variation (from orange to yellow) in the Cantabrian Mountains range (north of Spain) − is locally adapted to the pollinator community.Methods. We transplant orange-flowering individuals to a population with yellow-flowering individuals and vice-versa, to assess whether there is a pollination advantage in the local morph comparing its visitation rate with the foreign morph.Results. Our reciprocal transplant experiment showed no clear signal of local morph advantage at one site; thus, there is no evidence of local adaptation in Gentiana lutea to the pollinator assemblage. However, some floral visitor groups (such as Bombus pratorum, B. soroensis ancaricus and B. lapidarius decipiens) consistently preferred the local morph to the foreign morph whereas others (such as Bombus terrestris) consistently preferred the foreign morph.Discussion. We concluded that there is no evidence of local adaptation to the pollinator community in each of the two G. lutea populations studied. The consequences for local adaptation to pollinator on G. lutea flower color would depend on the variation along the Cantabrian Mountains range in morph frequency and pollinator community composition.