title: The role of pollinator diversity in the evolution of corolla-shape integration in a pollination-generalist plant clade.
abstract: Flowers of animal-pollinated plants are integrated structures shaped by the action of pollinator-mediated selection. It is widely assumed that pollination specialization increases the magnitude of floral integration. However, empirical evidence is still inconclusive. In this study, we explored the role of pollinator diversity in shaping the evolution of corolla-shape integration in Erysimum, a plant genus with generalized pollination systems. We quantified floral integration in Erysimum using geometric morphometrics and explored its evolution using phylogenetic comparative methods. Corolla-shape integration was low but significantly different from zero in all study species. Spatial autocorrelation and phylogenetic signal in corolla-shape integration were not detected. In addition, integration in Erysimum seems to have evolved in a way that is consistent with Brownian motion, but with frequent convergent evolution. Corolla-shape integration was negatively associated with the number of pollinators visiting the flowers of each Erysimum species. That is, it was lower in those species having a more generalized pollination system. This negative association may occur because the co-occurrence of many pollinators imposes conflicting selection and cancels out any consistent selection on specific floral traits, preventing the evolution of highly integrated flowers.
authors.affiliation: Department of Functional and Evolutionary Ecology, Estación Experimental de Zonas Áridas (EEZA-CSIC), University of Granada, Granada, Spain Department of Ecology, University of Granada, Granada, Spain jmgreyes@eeza.csic.es.
authors.forename: José María
authors.initials: JM
authors.lastname: Gómez
authors.affiliation: Department of Genetics, University of Granada, Granada, Spain.
authors.forename: Francisco
authors.initials: F
authors.lastname: Perfectti
authors.affiliation: Faculty of Life Sciences, University of Manchester, Dover Street, Manchester M13 9PL, UK.
authors.forename: Christian Peter
authors.initials: CP
authors.lastname: Klingenberg
mesh_terms: D000220:Adaptation, Biological / Q000502:physiology*; D000352:Africa, Northern; D000818:Animals; D001483:Base Sequence; D001499:Bayes Theorem; D044822:Biodiversity; D005075:Biological Evolution; D004275:DNA, Ribosomal / Q000235:genetics; D032601:Erysimum / Q000033:anatomy & histology*; D005060:Europe; D035264:Flowers / Q000033:anatomy & histology*; D007313:Insecta / Q000033:anatomy & histology* / Q000502:physiology; D008954:Models, Biological; D008957:Models, Genetic; D008969:Molecular Sequence Data; D010802:Phylogeny; D054817:Pollination / Q000502:physiology*; D017422:Sequence Analysis, DNA; D013045:Species Specificity
chemical_list: D004275:DNA, Ribosomal
keywords: Erysimum; floral integration; geometric morphometrics; phylogenetic comparative method; pollination generalization