目标:授粉者景观,根据传粉媒介的形态/行为确定,可以在特定范围内或特定范围内变化,施加不同的选择压力,并导致地理上不同的花卉生态型。由同一传粉者(传粉者行会)授粉的植物组合应表现出花性状的收敛,因为它们暴露于相似的选择压力下。融合和传粉生态型的形成都应导致植物及其传粉者之间性状的匹配。
方法:我们检查了17名花卉公会成员,他们在全部或部分范围内被Prosoecalongipennis授粉,舌长有地理差异的长长长状果蝇。有吸引力的花卉特征,如颜色,和花蜜特性记录在每个物种的种群中。花卉繁殖部分的长度,机械配合特征,在每个种群中记录,以评估与当地传粉者口器的可能相关性。使用多元回归分析来确定传粉者或非生物因素是否为花卉性状的变异提供了最佳解释,传粉者的变化记录在生外行会成员群体中。
结果:17个物种中有9个被其他地区的替代传粉者物种访问,这些表现出机械配合和吸引力特征的差异,提示推定的授粉生态型。在整个传粉者范围内,由P.longipennis授粉的植物的颜色相似。花卉公会成员的管长与龙氏疟原虫的长鼻长度共同变化。
结论:传粉媒介的变化导致了几个行会成员的传粉媒介生态型在地理上不同。然而,在网站内,不相关的植物授粉的P.longipennis是相似的,在他们的花部分的长度,最有可能是响应传粉媒介形态的趋同进化的结果。这两种证据表明,传粉媒介在选择某些花卉性状中起着重要作用。
OBJECTIVE: Pollinator landscapes, as determined by pollinator morphology/behaviour, can vary inter- or intraspecifically, imposing divergent selective pressures and leading to geographically divergent floral ecotypes. Assemblages of plants pollinated by the same pollinator (pollinator guilds) should exhibit convergence of floral traits because they are exposed to similar selective pressures. Both convergence and the formation of pollination ecotypes should lead to matching of traits among plants and their pollinators.
METHODS: We examined 17 floral guild members pollinated in all or part of their range by Prosoeca longipennis, a long-proboscid fly with geographic variation in tongue length. Attractive floral traits such as colour, and nectar properties were recorded in populations across the range of each species. The length of floral reproductive parts, a mechanical fit trait, was recorded in each population to assess possible correlation with the mouthparts of the local pollinator. A multiple regression analysis was used to determine whether pollinators or abiotic factors provided the best explanation for variation in floral traits, and pollinator shifts were recorded in extralimital guild member populations.
RESULTS: Nine of the 17 species were visited by alternative pollinator species in other parts of their ranges, and these displayed differences in mechanical fit and attractive traits, suggesting putative pollination ecotypes. Plants pollinated by P. longipennis were similar in colour throughout the pollinator range. Tube length of floral guild members co-varied with the proboscis length of P. longipennis.
CONCLUSIONS: Pollinator shifts have resulted in geographically divergent pollinator ecotypes across the ranges of several guild members. However, within sites, unrelated plants pollinated by P. longipennis are similar in the length of their floral parts, most probably as a result of convergent evolution in response to pollinator morphology. Both of these lines of evidence suggest that pollinators play an important role in selecting for certain floral traits.