Facultad de Biología, Universidad Michoacana de San Nicolás de Hidalgo, Morelia, Michoacán, México.
Plant Biol (Stuttg). 2018 Jan;20(1):160-164. doi: 10.1111/plb.12653. Epub 2017 Nov 21.
In sexually dimorphic species, hermaphrodite flowers in gynodioecious species or male flowers in dioecious species are often larger and produce more nectar than their conspecific female flowers. As a consequence, hermaphrodite or male flowers frequently receive more pollinator visits. Sex ratio, flower size, floral display, nectar production and floral visits were evaluated in two natural populations of Fuchsia thymifolia, a morphologically gynodioecious but functionally subdioecious insect-pollinated shrub. Sex ratio did not differ from the expected 1:1 in the two studied populations. As expected, hermaphrodite flowers were larger than female flowers, but in contrast to the general pattern, hermaphrodite flowers did not produce nectar or produced much less than female flowers. Flower visitors were flies (68%) and bumblebees (24%), both of which showed a preference for female flowers. No sex difference was detected in either flower longevity or floral display across the flowering season. Higher nectar production by females may attract more pollinators, and may be a strategy to enhance female reproductive success in this species. Finally, floral dimorphism and insect preferences did not seem to hamper the maintenance of sub-dioecy or prevent the evolution of dioecy in F. thymifolia.
在性二态物种中，雌雄同体花在雌雄异株物种中或雄花在雌雄同株物种中通常比同种的雌性花更大，产生更多的花蜜。因此，雌雄同体或雄性花经常会收到更多的传粉者访问。在形态上为雌雄异株但功能上为雌雄同株的虫媒授粉灌木智利风铃草的两个自然种群中，评估了性别比例、花大小、花展示、花蜜产量和花访问。在两个研究种群中，性别比例与预期的 1:1 没有差异。正如预期的那样，雌雄同体花比雌花大，但与一般模式相反，雌雄同体花不产生花蜜或产生的花蜜比雌花少得多。花访客是苍蝇（68%）和熊蜂（24%），它们都更喜欢雌花。在整个花期，花的寿命或花的展示都没有发现性别差异。雌性较高的花蜜产量可能会吸引更多的传粉者，并且可能是增强该物种雌性生殖成功的一种策略。最后，花的二态性和昆虫的偏好似乎并没有阻碍智利风铃草亚雌雄同株的维持或阻止其向雌雄同株的进化。
