Data from: Pollinator-mediated selection in a specialized hummingbird-Heliconia system in the eastern Caribbean

Phenotypic matches between plants and their pollinators often are interpreted as examples of reciprocal selection and adaptation. For the two co-occurring plant species, Heliconia bihai and H. caribaea in the Eastern Caribbean, we evaluated for five populations over two years the strength and direction of natural selection on corolla length and number of bracts per inflorescence. These plant traits correspond closely to the bill lengths and body masses of their primary pollinators, female or male purple-throated carib hummingbirds (Eulampis jugularis). In H. bihai, directional selection for longer corollas was always significant with the exception of one population in one year, whereas selection on bract numbers was rare and found only in one population in one year. In contrast, significant directional selection for more bracts per inflorescence occurred in all three populations of the yellow morph and in two populations of the red morph of H. caribaea, whereas significant directional selection on corolla length occurred in only one population of the red morph and one population of the yellow morph. Selection for longer corollas in H. bihai may result from better mechanical fit, and hence pollination, by the long bills of female E. jugularis, their sole pollinator. In contrast, competition between males of E. jugularis for territories may drive selection for more bracts in H. caribaea. Competitive exclusion of female E. jugularis by territorial males also implicates pollinator competition as a possible ecological mechanism for trait diversification in these plants.

植物与其传粉者间的表型匹配常被视为相互选择与适应的典型范例。针对东加勒比地区的两个同域蝎尾蕉属物种——比克蝎尾蕉（Heliconia bihai）与加勒比蝎尾蕉（Heliconia caribaea），我们在两年内对5个种群展开评估，以测定其花冠长度与每花序苞片数所承受的自然选择强度与方向。
上述植物性状与其主要传粉者——雌性或雄性紫喉加勒比蜂鸟（Eulampis jugularis）的喙长及体质量高度契合。
就比克蝎尾蕉而言，除单个种群在单一年份外，针对更长花冠的定向选择始终显著；而针对苞片数的选择则极为少见，仅在单个种群的单一年份被观测到。
与之形成鲜明对比的是，针对每花序更多苞片的显著定向选择，出现在加勒比蝎尾蕉黄色色型的全部3个种群，以及红色色型的2个种群中；而针对花冠长度的显著定向选择，仅在红色色型的1个种群与黄色色型的1个种群中被检测到。
比克蝎尾蕉中针对更长花冠的选择，可能源于其唯一传粉者——雌性紫喉加勒比蜂鸟的长喙带来的更佳机械适配性，进而提升传粉效果。与之相反，紫喉加勒比蜂鸟雄性间的领地竞争，可能驱动加勒比蝎尾蕉朝向更多苞片的性状演化。领地雄性对雌性紫喉加勒比蜂鸟的竞争排斥，也提示传粉者竞争或是推动这些植物产生性状分化的潜在生态机制。