Selection toward shorter flowers by butterflies whose probosces are shorter than floral tubes.
Darwin's meticulous observations on the function of floral shape led to his famous prediction of a long-tongued pollinator, which he believed to be the evolutionary trigger for the long-spurred flowers of the Madagascar star orchid. Although tubular flowers are common, long tubes or spurs are an exception, suggesting that selection maintaining short flowers is widespread. Using the butterfly-pollinated carnation Dianthus carthusianorum and two butterfly species differing in proboscis length (Melanargia galathea and Inachis io) as model organisms, we experimentally demonstrate a reduction in pollinator efficiency with an increasing difference between proboscis length and floral tube length. Such a relationship is a prerequisite for the evolution of floral shape in response to pollinator morphology.
Bloch
Daniel
D
Department of Environmental Sciences, Section Conservation Biology (NLU), University of Basel, St. Johanns-Vorstadt 10, CH-4056 Basel, Switzerland.
Erhardt
Andreas
A
D000818:Animals; D002080:Butterflies / Q000033:anatomy & histology* / Q000235:genetics* / Q000502:physiology; D029749:Dianthus / Q000033:anatomy & histology / Q000235:genetics / Q000502:physiology; D035264:Flowers / Q000033:anatomy & histology* / Q000235:genetics* / Q000502:physiology; D008954:Models, Biological; D012641:Selection, Genetic