title: Local adaptation: Mechanical fit between floral ecotypes of Nerine humilis (Amaryllidaceae) and pollinator communities.
abstract: Geographic variation in floral morphology is often assumed to reflect geographic variation in pollinator communities and associated divergence in selective pressures. We studied populations of Nerine humilis (Amaryllidaceae) to assess whether geographic variation in floral form is the result of local adaptation to different pollinator communities. We first tested for associations between floral traits and visitor communities, and found that populations with similar floral morphologies were visited by similar insect communities. Mean style length in each population was also closely associated with the mean body length of the local visitor community. A reciprocal translocation experiment demonstrated that native phenotypes set more seed than translocated phenotypes. Single visitation experiments showed that native flowers received more pollen, and set more seed per visit, than introduced phenotypes in both populations. This suggests that the effectiveness of pollinator visits is determined by the degree of mechanical fit between flowers and visitors. We provide strong evidence that the observed among-population variation in floral traits is an adaptive response to geographic variation in the pollinator community.
authors.affiliation: Department of Botany and Zoology, University of Stellenbosch, Private Bag X1, Matieland, 7602, South Africa.
authors.forename: Ethan
authors.initials: E
authors.lastname: Newman
authors.affiliation: South African National Biodiversity Institute, Private Bag X7, Claremont, Cape Town, 7735, South Africa.|Research Centre for Plant Growth and Development, School of Life Sciences, University of KwaZulu-Natal, Pietermaritzburg, Private Bag X01, Scottsville, 3209, South Africa.
authors.forename: John
authors.initials: J
authors.lastname: Manning
authors.affiliation: Department of Botany and Zoology, University of Stellenbosch, Private Bag X1, Matieland, 7602, South Africa. banderso.bruce@gmail.com.
authors.forename: Bruce
authors.initials: B
authors.lastname: Anderson
mesh_terms: D000818:Animals; D049628:Body Size; D060146:Ecotype; D035264:Flowers / Q000033:anatomy & histology*; D005843:Geography; D007313:Insecta / Q000033:anatomy & histology*; D019668:Liliaceae / Q000033:anatomy & histology / Q000235:genetics / Q000502:physiology*; D010641:Phenotype; D054817:Pollination; D012098:Reproduction / Q000502:physiology; D013019:South Africa
keywords: Advergent evolution; ecological speciation; long-proboscid fly; mechanical fit; pollination ecotypes; reciprocal translocation