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

Abstract

BackgroundThe adaptive maintenance of flower color variation is frequently attributed to pollinators partly because they preferentially visit certain flower phenotypes. We tested 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.MethodsWe transplanted orange-flowering individuals to a population with yellow-flowering individuals and vice versa, in order to assess whether there is a pollination advantage in the local morph by comparing its visitation rate with the foreign morph.ResultsOur reciprocal transplant experiment did not show clear local morph advantage in overall visitation rate: local orange flowers received more visits than foreign yellow flowers in the orange population, while both local and foreign flowers received the same visits in the yellow population; 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.DiscussionWe 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.

Geographic Variation in Floral Color and Reflectance Correlates With Temperature and Colonization History

“…Floral coloration can have strong effects on plant-pollinator interactions (e.g., Gigord et al., 2001 ; Guitián et al., 2017 ), and recent evidence highlights its impact on the microclimate experienced by pollen and ovules ( Lacey et al., 2010 ; Koski and Ashman, 2015 ; van der Kooi et al., 2019 ). Correlating geographic variation in petal coloration with ecological parameters such as pollinator communities or climatic conditions is one approach that can elucidate the degree to which putative selective agents may shape the evolution of color across large spatial scales ( Brunet, 2009 ; Sobral et al., 2015 ).…”