title: Dark purple nectar as a foraging signal in a bird-pollinated Himalayan plant.
abstract: • Some plants secrete coloured nectar to attract pollinators, but little is known about the chemical origins of nectar colouration and its ecological function. Leucosceptrum canum stands out as the only plant with coloured nectar recorded in the Himalayas. Here, we focused on the compound associated with the dark colour of the nectar, as well as its secretion dynamics during the flowering season and its relationship to pollinators. • Fresh nectar was analysed by semi-preparative reversed-phase high-performance liquid chromatography (HPLC), LC-MS and HRESIMS (high resolution electronspray ionization mass spectroscopy) to determine which compound causes the nectar colouration. Behavioural experiments were conducted with birds and honeybees to elucidate the effect of the nectar colour and volume on pollinators. • We identified a purple anthocyanidin, 5-hydroxyflavylium, as a natural nectar product for the first time. Two short-billed birds were found to pollinate this plant, which employs two nectar-based mechanisms to direct bird pollinators to reproductively active flowers, controlling nectar palatability and presenting a foraging signal for birds by altering nectar volume and colour in a developmental stage-specific manner. • 5-Hydroxyflavylium was found to be the cause of the nectar colouration, the function of which is to act as a foraging signal to increase pollination efficiency through nectar visibility and palatability.
authors.affiliation: Key Laboratory of Biodiversity and Biogeography, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650204, China.
authors.forename: Feng-Ping
authors.initials: FP
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650204, China.
authors.forename: Xiang-Hai
authors.initials: XH
authors.lastname: Cai
authors.affiliation: Key Laboratory of Biodiversity and Biogeography, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650204, China.
authors.forename: Hong
authors.initials: H
authors.lastname: Wang
authors.affiliation: Plant Germplasm and Genomics Center, Germplasm Bank of Wild Species, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650204, China.
authors.forename: Zong-Xin
authors.initials: ZX
authors.lastname: Ren
authors.affiliation: Plant Germplasm and Genomics Center, Germplasm Bank of Wild Species, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650204, China.
authors.forename: Zachary
authors.initials: Z
authors.lastname: Larson-Rabin
authors.affiliation: Key Laboratory of Biodiversity and Biogeography, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650204, China.|Plant Germplasm and Genomics Center, Germplasm Bank of Wild Species, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650204, China.
authors.forename: De-Zhu
authors.initials: DZ
authors.lastname: Li
mesh_terms: D000818:Animals; D001522:Behavior, Animal / Q000502:physiology*; D001717:Birds / Q000502:physiology*; D002241:Carbohydrates / Q000032:analysis; D017753:Ecosystem; D035264:Flowers; D005638:Fruit / Q000254:growth & development; D019686:Lamiaceae / Q000254:growth & development / Q000502:physiology*; D010858:Pigmentation / Q000502:physiology*; D057048:Plant Nectar / Q000378:metabolism*; D054817:Pollination / Q000502:physiology*; D019655:Quantitative Trait, Heritable; D012639:Seeds / Q000254:growth & development
chemical_list: D002241:Carbohydrates; D057048:Plant Nectar