title: Selection on pollen and pistil traits during pollen competition is affected by both sexual conflict and mixed mating in a self-compatible herb.
abstract: OBJECTIVE
  Although much attention has focused on the diversity of plant mating systems, only a few studies have considered the joint effects of mating system and sexual conflict in plant evolution. In mixed-mating Collinsia heterophylla, a sexual conflict over timing of stigma receptivity is proposed: pollen with a capacity to induce early onset of stigma receptivity secures paternity for early-arriving pollen (at the expense of reduced maternal seed set), whereas late onset of stigma receptivity mitigates the negative effects of early-arriving pollen. Here we investigated whether selection on pollen and pistil traits involved in sexual conflict is affected by the presence of both outcross- and self-pollen (mixed mating) during pollen competition.
  
  
  METHODS
  We conducted two-donor crosses at different floral developmental stages to explore male fitness (siring ability) and female fitness (seed set) in relation to male and female identity, pollen and pistil traits, and type of competitor pollen (outcross vs. self).
  
  
  RESULTS
  Late-fertilizing pollen rather than rapidly growing pollen tubes was most successful in terms of siring success, especially in competition with self-pollen after pollination at early floral stages. Late stigma receptivity increased seed set after early-stage pollinations, in agreement with selection against antagonistic pollen.
  
  
  CONCLUSIONS
  Selection on pollen and pistil traits in C. heterophylla is affected by both sexual conflict and mixed mating, suggesting the importance of jointly considering these factors in plant evolution.
authors.affiliation: Swedish University of Agricultural Sciences, Plant Protection Biology, P.O. Box 102, S-230 53 Alnarp, Sweden Biodiversity, Department of Biology, Lund University, Ecology Building, S-223 62 Lund, Sweden asa.lankinen@slu.se.
authors.forename: Åsa
authors.initials: Å
authors.lastname: Lankinen
authors.affiliation: Biodiversity, Department of Biology, Lund University, Ecology Building, S-223 62 Lund, Sweden Center for Environmental and Climate Research, Lund University, S-223 62 Lund, Sweden.
authors.forename: Henrik G
authors.initials: HG
authors.lastname: Smith
authors.affiliation: Biodiversity, Department of Biology, Lund University, Ecology Building, S-223 62 Lund, Sweden.
authors.forename: Stefan
authors.initials: S
authors.lastname: Andersson
authors.affiliation: Biodiversity, Department of Biology, Lund University, Ecology Building, S-223 62 Lund, Sweden.
authors.forename: Josefin A
authors.initials: JA
authors.lastname: Madjidian
mesh_terms: D003433:Crosses, Genetic; D008954:Models, Biological; D010943:Plantago / Q000502:physiology*; D010946:Plants, Medicinal / Q000502:physiology*; D011058:Pollen / Q000502:physiology*; D054817:Pollination; D019655:Quantitative Trait, Heritable; D012639:Seeds / Q000502:physiology; D057945:Self-Fertilization / Q000502:physiology*
keywords: Collinsia heterophylla; Plantaginaceae; cryptic self-incompatibility; mating system evolution; mixed mating; pollen competition; sexual conflict; sexual selection; timing of stigma receptivity