title: Oviposition by mutualistic seed-consuming pollinators reduces fruit abortion in a recently discovered pollination mutualism.
abstract: A prerequisite for the evolutionary stability of pollinating seed-consuming mutualisms is that each partner benefits from the association. However, few studies of such mutualism have considered the benefit gained by the pollinators. Here, we determined how the pollinating seed-predators ensure the provisioning of their offspring in the recently discovered mutualism between Rheum nobile and Bradysia flies. The correlation between flower fate and fly oviposition was examined. Floral traits and patterns of variation in fruit abortion and fly oviposition were investigated to determine whether female flies exhibit preferences for particular flowers when laying eggs. Indole-3-acetic acid (IAA) was quantified to determine whether female flies manipulate host physiology. Flowers that flies oviposited on had a significantly lower probability of fruit abortion compared with intact flowers. Females did not exhibit oviposition preference for any of the floral traits examined. There was no significant correlation between fruit abortion and fly oviposition in terms of either flower position or timing of flowering. IAA concentrations in oviposited flowers were significantly higher than in intact flowers. Our results suggest that oviposition by the mutualistic seed-consuming pollinator Bradysia sp., greatly reduces the probability of fruit abortion of its host, R. nobile; this may be attributed to the manipulation of host physiology through regulating IAA levels.
authors.affiliation: Key Laboratory for Plant Diversity and Biogeography of East Asian, Kunming Institute of Botany, Chinese Academy of Sciences, 132 Lanhei Road, Kunming 650201, Yunnan, PR China.
authors.forename: Bo
authors.initials: B
authors.lastname: Song
authors.affiliation: Institute of Botany, University of Basel, Schönbeinstr 6, Basel 4056, Switzerland.
authors.forename: Jürg
authors.initials: J
authors.lastname: Stöcklin
authors.affiliation: Yunnan Forestry Technological College, 1 Chuanjin Road, Kunming 650224, Yunnan, PR China.
authors.forename: Yong-Qian
authors.initials: YQ
authors.lastname: Gao
authors.affiliation: Key Laboratory for Plant Diversity and Biogeography of East Asian, Kunming Institute of Botany, Chinese Academy of Sciences, 132 Lanhei Road, Kunming 650201, Yunnan, PR China.
authors.forename: De-Li
authors.initials: DL
authors.lastname: Peng
authors.affiliation: Key Laboratory for Plant Diversity and Biogeography of East Asian, Kunming Institute of Botany, Chinese Academy of Sciences, 132 Lanhei Road, Kunming 650201, Yunnan, PR China.
authors.forename: Min-Shu
authors.initials: MS
authors.lastname: Song
authors.affiliation: Key Laboratory for Plant Diversity and Biogeography of East Asian, Kunming Institute of Botany, Chinese Academy of Sciences, 132 Lanhei Road, Kunming 650201, Yunnan, PR China.
authors.forename: Hang
authors.initials: H
authors.lastname: Sun
mesh_terms: D000818:Animals; D005075:Biological Evolution; D035264:Flowers / Q000254:growth & development*; D005638:Fruit / Q000254:growth & development; D009036:Moths / Q000254:growth & development; D010058:Oviposition / Q000502:physiology*; D054817:Pollination / Q000502:physiology; D012639:Seeds / Q000737:chemistry; D013559:Symbiosis / Q000502:physiology*