Moir Matthew, Butler Hannah, Peter Craig, Dold Tony, Newman Ethan
Department of Botany, Rhodes University, Makhanda, 6140, South Africa.
New Phytol. 2025 Mar;245(5):2322-2335. doi: 10.1111/nph.20373. Epub 2025 Jan 10.
Pollinators are thought to play a key role in driving incipient speciation within the angiosperms. However, the mechanisms underlying floral divergence in plants with generalist pollination systems, remains understudied. Brunsvigia gregaria displays significant geographical variation in floral traits and are visited by diverse pollinator communities. Because pollinators are often shared between populations, we investigated whether specific pollinators are responsible for driving floral divergence between them. Three distinct ecotypes were identified, each dominated by three different pollinators: bees, swallowtail butterflies, and long-proboscid flies. Across seven populations, we found a pattern of association between style length and the morphology of pollinators that visit the flowers most frequently and contact the reproductive parts most often. Furthermore, we found significant linear, quadratic and correlational selection on flower number, tepal length and style length within the butterfly- and bee-dominated populations. We also found partial evidence for divergent selection on these traits between experimental sites. Our findings suggest that a handful of key pollinators that vary in their importance have the potential to drive population-level divergence in floral traits, which may lead to pollination ecotype formation.
传粉者被认为在被子植物的初始物种形成过程中发挥着关键作用。然而，对于具有泛化传粉系统的植物，其花部差异背后的机制仍未得到充分研究。群居布氏鸢尾在花部特征上表现出显著的地理变异，且有不同的传粉者群落对其进行访花。由于传粉者通常在不同种群间共享，我们研究了特定传粉者是否导致了不同种群间的花部差异。我们识别出了三种不同的生态型，每种生态型由三种不同的传粉者主导：蜜蜂、燕尾蝶和长喙蝇。在七个种群中，我们发现花柱长度与最常访花并最常接触生殖部位的传粉者形态之间存在关联模式。此外，在以蝴蝶和蜜蜂为主导的种群中，我们发现了对花数量、花被片长度和花柱长度的显著线性、二次和相关选择。我们还发现了实验地点之间在这些性状上存在趋异选择的部分证据。我们的研究结果表明，少数重要性不同的关键传粉者有可能推动花部性状的种群水平差异，这可能导致传粉生态型的形成。
