Queiroz Joel A, Quirino Zelma G M, Machado Isabel C
Programa de Pós-Graduação em Biologia Vegetal, Departamento de Botânica, CCB, Universidade Federal de Pernambuco, 50372-970 Recife, PE, Brazil.
Departamento de Engenharia e Meio Ambiente, CCAE, Universidade Federal da Paraíba, Rio Tinto, PB, Brazil.
AoB Plants. 2015 Nov 10;7:plv127. doi: 10.1093/aobpla/plv127.
Floral attributes evolve in response to frequent and efficient pollinators, which are potentially important drivers of floral diversification and reproductive isolation. In this context, we asked, how do flowers evolve in a bat-hummingbird pollination system? Hence, we investigated the pollination ecology of two co-flowering Ipomoea taxa (I. marcellia and I. aff. marcellia) pollinated by bats and hummingbirds, and factors favouring reproductive isolation and pollinator sharing in these plants. To identify the most important drivers of reproductive isolation, we compared the flowers of the two Ipomoea taxa in terms of morphometry, anthesis and nectar production. Pollinator services were assessed using frequency of visits, fruit set and the number of seeds per fruit after visits. The studied Ipomoea taxa differed in corolla size and width, beginning and duration of anthesis, and nectar attributes. However, they shared the same diurnal and nocturnal visitors. The hummingbird Heliomaster squamosus was more frequent in I. marcellia (1.90 visits h(-1)) than in I. aff. marcellia (0.57 visits h(-1)), whereas glossophagine bats showed similar visit rates in both taxa (I. marcellia: 0.57 visits h(-1) and I. aff. marcellia: 0.64 visits h(-1)). Bat pollination was more efficient in I. aff. marcellia, whereas pollination by hummingbirds was more efficient in I. marcellia. Differences in floral attributes between Ipomoea taxa, especially related to the anthesis period, length of floral parts and floral arrangement in the inflorescence, favour reproductive isolation from congeners through differential pollen placement on pollinators. This bat-hummingbird pollination system seems to be advantageous in the study area, where the availability of pollinators and floral resources changes considerably throughout the year, mainly as a result of rainfall seasonality. This interaction is beneficial for both sides, as it maximizes the number of potential pollen vectors for plants and resource availability for pollinators.
花的特征会随着频繁且高效的传粉者而进化，这些传粉者可能是花多样化和生殖隔离的重要驱动因素。在此背景下，我们提出疑问：在蝙蝠 - 蜂鸟传粉系统中花是如何进化的？因此，我们研究了两种共同开花的甘薯属类群（马赛甘薯和近马赛甘薯）由蝙蝠和蜂鸟传粉的传粉生态学，以及有利于这些植物生殖隔离和传粉者共享的因素。为了确定生殖隔离的最重要驱动因素，我们从形态测量、开花期和花蜜分泌方面比较了两种甘薯属类群的花。通过访问频率、坐果率以及访问后果实中的种子数量来评估传粉者服务。所研究的甘薯属类群在花冠大小和宽度、开花起始和持续时间以及花蜜特征方面存在差异。然而，它们拥有相同的白天和夜间访客。蜂鸟鳞喉太阳鸟在马赛甘薯（1.90次访问/小时）中比在近马赛甘薯（0.57次访问/小时）中更频繁，而长舌蝠在两个类群中的访问率相似（马赛甘薯：0.57次访问/小时，近马赛甘薯：0.64次访问/小时）。蝙蝠传粉在近马赛甘薯中更有效，而蜂鸟传粉在马赛甘薯中更有效。甘薯属类群之间花的特征差异，特别是与开花期、花部长度和花序中的花排列有关的差异，通过传粉者上不同的花粉放置有利于与同属植物的生殖隔离。这种蝙蝠 - 蜂鸟传粉系统在研究区域似乎是有利的，在该区域，传粉者和花资源的可用性全年变化很大，主要是由于降雨季节性。这种相互作用对双方都有益，因为它使植物潜在花粉传播者的数量最大化以及传粉者的资源可用性最大化。
