title: Asymmetrical disassortative pollination in a distylous primrose: the complementary roles of bumblebee nectar robbers and syrphid flies.
abstract: Heterostyly is a floral polymorphism characterized by reciprocal herkogamy maintained through high levels of mating between morphs, serviced by appropriate pollinators. We studied how differential efficiency and abundance of distinct pollinators affect plant female reproduction in self- and intra-morph incompatible distylous Primula secundiflora. Bumblebees and syrphid flies were found to be the most abundant floral visitors. Bumblebees frequently exhibited nectar-robbing behavior. Because the robbing holes were always situated between the high- and low-level organs on both morphs, nectar-robbing bumblebees only pollinated S-styled flowers. L-styled flowers set four times as many seeds as did S-styled flowers after being visited by pollen-collecting syrphid flies. The natural female fecundity and the magnitude of pollen limitation varied between the morphs within populations because of the mosaic distribution of nectar-robbing bumblebees and syrphid flies. L-styled flowers and S-styled flowers set the same number of seeds after supplemental hand pollination, indicating equivalent female reproductive potential. We suggest that bumblebee nectar robbers and syrphid flies play an important role in sustaining the floral dimorphism of heterostyly in P. secundiflora because of their complementary roles in the pollination system.
authors.affiliation: 1] Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, 666303, China [2] University of Chinese Academy of Sciences, 10049, China.
authors.forename: Xing-Fu
authors.initials: XF
authors.lastname: Zhu
authors.affiliation: 1] Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, 666303, China [2] University of Chinese Academy of Sciences, 10049, China.
authors.forename: Xian-Feng
authors.initials: XF
authors.lastname: Jiang
authors.affiliation: 1] Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, 666303, China [2] University of Chinese Academy of Sciences, 10049, China.
authors.forename: Li
authors.initials: L
authors.lastname: Li
authors.affiliation: Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650204, China.
authors.forename: Zhi-Qiang
authors.initials: ZQ
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, 666303, China.
authors.forename: Qing-Jun
authors.initials: QJ
authors.lastname: Li
mesh_terms: D000818:Animals; D001516:Bees / Q000502:physiology*; D002681:China; D004175:Diptera / Q000502:physiology*; D035264:Flowers / Q000502:physiology; D005638:Fruit / Q000254:growth & development; D005843:Geography; D057048:Plant Nectar / Q000378:metabolism*; D054817:Pollination / Q000502:physiology*; D031825:Primula / Q000502:physiology*; D012639:Seeds / Q000254:growth & development
chemical_list: D057048:Plant Nectar