title: Parthenogenesis maintains male sterility in a gynodioecious orchid.
abstract: The invasion of male-sterile (female) individuals into hermaphroditic populations, leading to gynodioecy, is common in flowering plants. Both theoretical and empirical studies have shown that as the frequency of females increases in a population, pollen limitation reduces seed production more in females than in hermaphrodites, leading to higher fitness for hermaphrodites and a consequent decrease in female frequency. Here we show that contrary to this expectation, females of the gynodioecious orchid Satyrium ciliatum are maintained only in populations that experience high pollen limitation caused by low pollinator service and high pollen herbivory. This species avoids the typical problem of pollen limitation for seed production and can therefore maintain high frequencies of females in pollen-limited populations because females produce more seeds than hermaphrodites via facultative parthenogenesis in the absence of pollinia. Our results therefore demonstrate that parthenogenesis is a novel mechanism favoring the maintenance of gynodioecy.
authors.affiliation: College of Life Sciences, Wuhan University, Wuhan 430072, China. sqhuang@whu.edu.cn
authors.forename: Shuang-Quan
authors.initials: SQ
authors.lastname: Huang
authors.forename: Yang
authors.initials: Y
authors.lastname: Lu
authors.forename: Ying-Zhuo
authors.initials: YZ
authors.lastname: Chen
authors.forename: Yi-Bo
authors.initials: YB
authors.lastname: Luo
authors.forename: Lynda F
authors.initials: LF
authors.lastname: Delph
mesh_terms: D000818:Animals; D001516:Bees; D029595:Orchidaceae / Q000502:physiology*; D010312:Parthenogenesis; D051479:Plant Infertility; D054817:Pollination; D012639:Seeds / Q000254:growth & development