Evolution of pollinator specialization and de-specialization in Echinopsis (Cactaceae, Trichocereeae)

刺头属（仙人掌科、毛头菌科）传粉者特化和去特化的进化

• 批准号: 20783143
• 负责人: Dr. Boris Schlumpberger
• 金额: --
• 依托单位: Herrenhäuser Gärten
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2005
• 资助国家: 德国
• 起止时间: 2004-12-31 至 2010-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/20783143?language=en
• 关键词: Evolution; pollinator; specialization; de; Echinopsis

When plant species disperse to new habitats, they often encounter a new pollinator fauna and undergo changes in floral morphology resulting from divergent pollinator selection regimes. This is thought to contribute to species formation when the divergent forms later come into secondary contact but can no longer produce fit offspring. The proposed research will examine pollination in six small clades of Cactaceae, each with 3-5 very closely related species (divergent sets of populations), in order to examine which morphological and physiological flower traits correlate with shifts between bee, hummingbird, and hawkmoth pollination. The focal clades, which belong to the large genus Echinopsis (Trichocereeae), were selected because preliminary data suggest that pollinators play a role in species divergence and reproductive isolation; there are also cases of apparent bimodal pollination strategies. We hypothesize that shifts from hawkmoth to bee pollination are relatively easy while shifts from bee to bird or hawkmoth pollination are more difficult. All three pollination syndromes involve numerous traits besides the actual rewards (nectar and/or pollen), and this project will focus on changes in floral scents that correlate with the six possible directions of pollinator change. By focusing on several small clades we will be able to combine field observations at several sites with species/population-level phylogenetic analyses and biochemical analyses of floral odor. Together, these components will allow to assess whether more derived (younger) species tend to rely on fewer pollinators and thus are more specialized or whether on the contrary they rely on more kinds of pollinators and thus stay, or become, unspecialized. This will be only the second study to address this question and the first to assess the role of odor bouquets in the broadening or narrowing of pollinator spectra.

当植物物种分散到新的栖息地时，它们经常会遇到新的传粉媒介动物群，并且由于不同的传粉媒介选择制度而导致花卉形态发生变化。当不同的形式后来进行二次接触但不能再产生合适的后代时，这被认为有助于物种的形成。拟议的研究将检查仙人掌科的六个小分支的授粉，每个分支都有 3-5 个非常密切相关的物种（不同的种群集合），以检查哪些形态和生理花朵特征与蜜蜂、蜂鸟和天蛾授粉之间的变化相关。选择属于大属 Echinopsis (Trichocereeae) 的焦点进化枝，是因为初步数据表明传粉媒介在物种分化和生殖隔离中发挥着作用；还存在明显的双峰授粉策略的情况。我们假设从天蛾授粉到蜜蜂授粉的转变相对容易，而从蜜蜂到鸟类或天蛾授粉的转变则更加困难。除了实际奖励（花蜜和/或花粉）之外，所有三种授粉综合症都涉及许多特征，该项目将重点关注与授粉媒介变化的六个可能方向相关的花香的变化。通过关注几个小进化枝，我们将能够将多个地点的实地观察与物种/种群水平的系统发育分析和花气味的生化分析结合起来。总之，这些组成部分将允许评估更多衍生（较年轻）的物种是否倾向于依赖较少的授粉媒介，从而更加专业化，或者是否相反，它们依赖更多种类的授粉媒介，从而保持或变得非专业化。这将是解决这个问题的第二项研究，也是第一项评估气味花束在扩大或缩小传粉媒介光谱中的作用的研究。