title: Pollinator-mediated competition influences selection for flower-color displacement in sympatric monkeyflowers.
abstract: OBJECTIVE
  When coflowering plant species share pollinators, pollinator-mediated competition may favor divergent floral characters associated with pollinator attraction. One potential outcome of this process is that sympatric populations will display increased divergence in floral traits compared with allopatric populations. We developed a new system to study the pattern and process of character displacement. In the central Sierra Nevada of California, USA, Mimulus bicolor is a spring wildflower with two flower-color morphs, one of which resembles coflowering M. guttatus.
  
  
  METHODS
  We documented a fine-scale geographic pattern of character displacement in sympatric and allopatric patches and, using experimental arrays, measured seed set in M. bicolor color morphs in the presence versus absence of M. guttatus.
  
  
  RESULTS
  In sympatric arrays yellow, guttatus-like M. bicolor morphs had lower relative fitness (0.35 ± 0.05) and reduced conspecific pollen deposition compared with the distinct alternative morph, whereas in allopatric arrays yellow, guttatus-like morphs were occasionally strongly favored.
  
  
  CONCLUSIONS
  Pollinator-mediated competition with M. guttatus is consistent with ecological character displacement in M. bicolor and likely contributes to a geographic pattern of character displacement.
authors.affiliation: Department of Plant Biology, University of Minnesota, St. Paul, Minnesota 55108 USA.
authors.forename: Dena L
authors.initials: DL
authors.lastname: Grossenbacher
authors.affiliation: Department of Evolution and Ecology, Center for Population Biology, University of California, Davis, California 95616 USA.
authors.forename: Maureen L
authors.initials: ML
authors.lastname: Stanton
mesh_terms: D000818:Animals; D001522:Behavior, Animal; D002140:California; D003116:Color; D035264:Flowers / Q000033:anatomy & histology* / Q000235:genetics / Q000502:physiology; D007313:Insecta / Q000502:physiology*; D032241:Mimulus / Q000033:anatomy & histology* / Q000235:genetics / Q000502:physiology; D010641:Phenotype; D011058:Pollen / Q000033:anatomy & histology / Q000235:genetics / Q000502:physiology; D054817:Pollination; D012639:Seeds / Q000033:anatomy & histology / Q000235:genetics / Q000502:physiology; D061350:Sympatry
keywords: M. guttatus; Mimulus bicolor; conspecific; ecological character displacement; heterospecific; natural selection; pollination; reproductive character displacement