Floral isolation and pollination in two hummingbird-pollinated heliconias data

Differences in feeding performance and aggressive abilities between species and sexes of hummingbirds are often associated with the partitioning of their food sources, but whether such partitioning results in floral isolation (reproductive isolation at the stage of pollination) has received little attention. We examined components of floral isolation and pollinator effectiveness of Heliconia caribaea and H. bihai on the island of Dominica, West Indies. The short flowers of H. caribaea match the short bills of male Anthracothorax jugularis, its primary pollinator, whereas the long flowers of H. bihai match the long bills of female A. jugularis, its primary pollinator. In pollination experiments, both sexes of A. jugularis were equally effective at pollinating the short flowers of H. caribaea, which they preferred to H. bihai, whereas females were more effective at pollinating the long flowers of H. bihai. Moreover, an average difference in length of 12 mm between H. caribaea and H. bihai...蜂鸟不同物种与性别间的取食性能与攻击能力差异，通常与其食物资源的分化密切相关，但此类分化是否会引发花隔离（传粉阶段的生殖隔离），相关研究仍较为匮乏。我们于西印度群岛多米尼加岛上，针对加勒比蝎尾蕉（Heliconia caribaea）与比亥蝎尾蕉（H. bihai）的花隔离组分及传粉者有效性开展了研究。其主要传粉者为绿喉芒果蜂鸟（Anthracothorax jugularis），该物种雄性个体的短喙与加勒比蝎尾蕉的短花型高度适配，而雌性个体的长喙则恰好契合比亥蝎尾蕉的长花结构。传粉实验结果表明，绿喉芒果蜂鸟的雌雄个体均能高效为加勒比蝎尾蕉的短花完成传粉，且相较于比亥蝎尾蕉，它们更偏好造访加勒比蝎尾蕉；而雌性蜂鸟则更擅长为比亥蝎尾蕉的长花完成传粉。此外，加勒比蝎尾蕉与比亥蝎尾蕉的花长平均相差12 mm……