DIMENSIONS: COLLABORATIVE RESEARCH: The evolution of pollination syndrome diversity in Penstemon

生态系统的健康和生产力取决于共同进化的物种相互作用。在陆地生态系统中，一个关键的相互作用是在花和传粉者之间，不同传粉者（如蜜蜂、鸟类）相对丰度的变化被认为施加了选择压力，可以改变花的授粉策略和塑造开花植物群落。然而，多种力量可能会限制开花植物谱系在不断变化的环境条件下进化出新的授粉策略的能力。本研究将模拟北美特有的最大开花植物属（Penstemon）的传粉策略转换速率，并将确定限制和塑造传粉策略多样化速率的生态和遗传过程。了解维持授粉策略多样性的力量，有助于解决粮食安全和农业管理问题。该研究整合了系统发育、生态和遗传方法，以了解决定授粉多样性的过程。这项研究将测试Penstemon是否在蜜蜂和蜂鸟授粉综合征的相对频率上达到了进化平衡。此外，计划中的实验将确定授粉综合征过渡、综合征特异性物种形成和灭绝率不对称的生态和遗传过程。田间实验将测试花性状之间的相互作用是否限制了从蜂鸟到蜜蜂授粉的转变。基因实验将测试对蜂鸟传粉至关重要的功能丧失突变是否也限制了从蜂鸟传粉到蜜蜂传粉的反向转变。这些实验方法的整合将阐明决定传粉综合征多样性在植物群落组合的过程。

Ecosystem health and productivity depend on co-evolved species interactions. In terrestrial ecosystems a key interaction is between flowers and pollinators, and changes in the relative abundances of different pollinators (e.g., bees, birds) are thought to impose selective pressures that can shift floral pollination strategies and shape flowering plant communities. However, multiple forces may act to constrain the ability of a flowering plant lineage to evolve a new pollination strategy under changing environmental conditions. This research will model the rate of pollination strategy transitions in the largest flowering plant genus endemic to North America (Penstemon), and will determine both ecological and genetic processes that constrain and shape the rate of pollination strategy diversification. Understanding the forces that maintain diversity in pollination strategies informs food security and agricultural management issues.The research integrates phylogenetic, ecological, and genetic approaches to understand the processes that determine pollination diversity. The research will test whether Penstemon has reached an evolutionary equilibrium in the relative frequencies of bee and hummingbird pollination syndromes. Additionally, the planned experiments will determine ecological and genetic processes responsible for asymmetries in pollination syndrome transitions, and in syndrome-specific speciation, and extinction rates. Field experiments will test whether interactions among floral traits constrain shifts from hummingbird to bee pollination. Genetic experiments will test whether loss-of-function mutations critical for shifts to hummingbird pollination also constrain reverse shifts from hummingbird to bee pollination. The integration of these experimental approaches will elucidate processes that determine pollination syndrome diversity in plant community assemblages.