title: Toward a predictive understanding of the fitness costs of heterospecific pollen receipt and its importance in co-flowering communities.
abstract: OBJECTIVE
  While we have a good understanding of how co-flowering plants interact via pollinator foraging, we still know very little about how plants interact via heterospecific pollen (HP) receipt. To fill this gap, we sought to illuminate the extent of HP receipt and quantitatively evaluate the fitness consequences of HP receipt. We consider plant traits that could mediate the fitness costs of HP receipt in an effort to better understand the potential consequences of pollinator sharing in natural communities. •
  
  
  METHODS
  We survey the literature for occurrence of HP receipt and assess variation in the fitness effects of a standard HP treatment. We develop a conceptual framework for understanding variation in fitness consequences of HP receipt. •
  
  
  RESULTS
  We find evidence for variation in HP receipt and its costs. Our framework predicts that certain traits (self-incompatibility, small, highly aperaturate or allelopathic pollen) will lead to detrimental HP donors, whereas others (self-compatibility, small or wet stigmas, short styles) will lead to vulnerable HP recipients. We also predict that detrimental effects of HP receipt will increase with decreasing phylogenetic distance between donor and recipient. •
  
  
  CONCLUSIONS
  Our framework can guide much needed additional work so that we can evaluate whether and which plant traits contribute to the variation in the effects of HP receipt. This will be a step toward predicting the consequences of HP receipt in natural communities, and ultimately transform our understanding of the role of postpollination interactions in floral trait evolution and pollinator sharing.
authors.affiliation: Department of Biological Sciences, University of Pittsburgh, 4249 Fifth Avenue, Pittsburgh, PA 15260-3929, USA. tia1@pitt.edu
authors.forename: Tia-Lynn
authors.initials: TL
authors.lastname: Ashman
authors.forename: Gerardo
authors.initials: G
authors.lastname: Arceo-Gómez
mesh_terms: D017753:Ecosystem; D035264:Flowers / Q000502:physiology*; D018506:Gene Expression Regulation, Plant / Q000502:physiology*; D056084:Genetic Fitness; D019684:Magnoliopsida / Q000235:genetics* / Q000502:physiology; D008954:Models, Biological; D011058:Pollen / Q000235:genetics / Q000502:physiology*; D012098:Reproduction / Q000235:genetics / Q000502:physiology; D013045:Species Specificity; D013997:Time Factors
keywords: community assembly; competition; facilitation; floral evolution; heterospecific pollen receipt; interspecific pollen transfer; invasive species; plant–plant interactions; pollinator sharing