title: An ultraviolet floral polymorphism associated with life history drives pollinator discrimination in Mimulus guttatus.
abstract: •
  
  
  OBJECTIVE
  Ultraviolet (UV) floral patterns are common in angiosperms and mediate pollinator attraction, efficiency, and constancy. UV patterns may vary within species, yet are cryptic to human observers. Thus, few studies have explicitly described the distribution or ecological significance of intraspecific variation in UV floral patterning. Here, we describe the geographic distribution and pattern of inheritance of a UV polymorphism in the model plant species Mimulus guttatus (Phrymaceae). We then test whether naturally occurring UV phenotypes influence pollinator interactions within M. guttatus.•
  
  
  METHODS
  We document UV patterns in 18 annual and 19 perennial populations and test whether UV pattern is associated with life history. To examine the pattern of inheritance, we conducted crosses within and between UV phenotypes. Finally, we tested whether bee pollinators discriminate among naturally occurring UV phenotypes in two settings: wild bee communities and captive Bombus impatiens.•
  
  
  RESULTS
  Within M. guttatus, perennial populations exhibit a small bulls-eye pattern, whereas a bilaterally symmetric runway pattern occurs mainly in annual populations. Inheritance of UV patterning is consistent with a single-locus Mendelian model in which the runway phenotype is dominant. Bee pollinators discriminate against unfamiliar UV patterns in both natural and controlled settings.•
  
  
  CONCLUSIONS
  We describe a widespread UV polymorphism associated with life history divergence within Mimulus guttatus. UV pattern influences pollinator visitation and should be considered when estimating reproductive barriers between life history ecotypes. This work develops a new system to investigate the ecology and evolution of UV floral patterning in a species with extensive genomic resources.
authors.affiliation: Ecology and Evolutionary Biology, University of California Santa Cruz, 1156 High Street, Santa Cruz, California 95064 USA.
authors.forename: Megan L
authors.initials: ML
authors.lastname: Peterson
authors.affiliation: Ecology and Evolutionary Biology, University of California Santa Cruz, 1156 High Street, Santa Cruz, California 95064 USA.
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Miller
authors.affiliation: Ecology and Evolutionary Biology, University of California Santa Cruz, 1156 High Street, Santa Cruz, California 95064 USA.
authors.forename: Kathleen M
authors.initials: KM
authors.lastname: Kay
mesh_terms: D000818:Animals; D001516:Bees / Q000502:physiology*; D005075:Biological Evolution; D003116:Color; D035264:Flowers / Q000235:genetics / Q000502:physiology*; D032241:Mimulus / Q000235:genetics / Q000502:physiology*; D010641:Phenotype; D054817:Pollination; D011110:Polymorphism, Genetic; D060047:Reproductive Isolation; D014466:Ultraviolet Rays; D014796:Visual Perception
keywords: Bombus impatiens; Phrymaceae; bumblebee; ethological isolation; floral constancy; life history; nectar guide; pollination ecology; pollinator isolation; ultraviolet