title: Sexual antagonism in the pistil varies among populations of a hermaphroditic mixed-mating plant.
abstract: Sexual conflicts and their evolutionary outcomes may be influenced by population-specific features such as mating system and ecological context; however, very few studies have investigated the link between sexual conflict and mating system. The self-compatible, mixed-mating hermaphrodite Collinsia heterophylla (Plantaginaceae) is thought to exhibit a sexual conflict over timing of stigma receptivity. This conflict involves (i) delayed stigma receptivity, which intensifies pollen competition, and (ii) early fertilization forced by pollen, which reduces seed set. We investigated the potential for the conflict to occur under field conditions and performed glasshouse crosses within eight populations to assess its consistency across populations. Flowers were visited, and produced seeds after pollination, at all developmental stages, suggesting that the conflict can be of significance under natural conditions. In the glasshouse, early pollination imposed costs in all populations. Overall, the timing of first seed set was most strongly affected by the maternal parent, denoting stronger female than male ability to influence the onset of stigma receptivity. Crosses also revealed a negative relationship between donor- and recipient-related onset of receptivity within individuals, a novel result hinting at trade-offs in sex allocation or a history of antagonistic selection. Neither timing of stigma receptivity, timing of first seed set, nor pollen competitive ability covaried with population outcrossing rate. In conclusion, these results indicate that sexually antagonistic selection may be present in varying degrees in different populations of C. heterophylla, but this variation does not appear to be directly related to mating system variation.
authors.affiliation: Biodiversity, Department of Biology, Lund University, Lund, Sweden.
authors.forename: E
authors.initials: E
authors.lastname: Hersh
authors.affiliation: Biodiversity, Department of Biology, Lund University, Lund, Sweden.
authors.forename: J A
authors.initials: JA
authors.lastname: Madjidian
authors.affiliation: Biodiversity, Department of Biology, Lund University, Lund, Sweden.
authors.forename: S
authors.initials: S
authors.lastname: Andersson
authors.affiliation: Swedish University of Agricultural Sciences, Plant Protection Biology, Alnarp, Sweden.
authors.forename: M
authors.initials: M
authors.lastname: Strandh
authors.affiliation: School of Biological Science, University of Portsmouth, Portsmouth, UK.|Institute of Arctic Biology, University of Alaska, Fairbanks, AK, USA.|Department of Biology, Norwegian University of Science and Technology, Trondheim, Norway.
authors.forename: W S
authors.initials: WS
authors.lastname: Armbruster
authors.affiliation: Swedish University of Agricultural Sciences, Plant Protection Biology, Alnarp, Sweden.
authors.forename: Å
authors.initials: Å
authors.lastname: Lankinen
mesh_terms: D000818:Animals; D001516:Bees; D002140:California; D003433:Crosses, Genetic; D035264:Flowers / Q000502:physiology*; D005828:Genetics, Population; D057048:Plant Nectar / Q000378:metabolism; D000068377:Plantaginaceae / Q000235:genetics / Q000502:physiology*; D011058:Pollen; D054817:Pollination; D012098:Reproduction / Q000502:physiology*; D012639:Seeds / Q000254:growth & development
chemical_list: D057048:Plant Nectar
keywords: Collinsia heterophylla; conflict cost; delayed stigma receptivity; mixed-mating; pollen competition; sexually antagonistic coevolution