title: Generalist passerine pollination of a winter-flowering fruit tree in central China.
abstract: OBJECTIVE
  Winter-flowering plants outside the tropics may experience a shortage of pollinator service, given that insect activity is largely limited by low temperature. Birds can be alternative pollinators for these plants, but experimental evidence for the pollination role of birds in winter-flowering plants is scarce.
  
  
  METHODS
  Pollinator visitation to the loquat, Eriobotrya japonica (Rosaceae), was observed across the flowering season from November to January for two years in central China. Self- and cross-hand pollination was conducted in the field to investigate self-compatibility and pollen limitation. In addition, inflorescences were covered by bird cages and nylon mesh nets to exclude birds and all animal pollinators, respectively, to investigate the pollination role of birds in seed production.
  
  
  RESULTS
  Self-fertilization in the loquat yielded few seeds. In early winter insect visit frequency was relatively higher, while in late winter insect pollinators were absent and two passerine birds (Pycnonotus sinensis and Zosterops japonicus) became the major floral visitors. However, seed-set of open-pollinated flowers did not differ between early and late winter. Exclusion of bird visitation greatly reduced seed-set, indicating that passerine birds were important pollinators for the loquat in late winter. The whitish perigynous flowers reward passerines with relatively large volumes of dilute nectar. Our observation on the loquat and other Rosaceae species suggested that perigyny might be related to bird pollination but the association needs further study.
  
  
  CONCLUSIONS
  These findings suggest that floral traits and phenology would be favoured to attract bird pollinators in cold weather, in which insect activity is limited.
authors: College of Life Sciences, Wuhan University, China.
authors: Qiang
authors: Q
authors: Fang
authors: Ying-Zhuo
authors: YZ
authors: Chen
authors: Shuang-Quan
authors: SQ
authors: Huang
mesh_terms: D000818:Animals; D002681:China; D003080:Cold Temperature; D031983:Eriobotrya / Q000502:physiology*; D035264:Flowers / Q000254:growth & development*; D007313:Insecta; D046109:Passeriformes; D011058:Pollen / Q000502:physiology; D054817:Pollination / Q000502:physiology*; D012098:Reproduction / Q000502:physiology; D012621:Seasons; D014197:Trees / Q000502:physiology*