Parental frequencies and spatial configuration shape bumblebee behavior and floral isolation in hybridizing Rhinanthus

To shed light on the role played by pollinators in the diversification of angiosperms, focus is needed on how floral isolation varies locally in the early stages of plant divergence. The few studies performed so far have often used species pairs with distinct pollination syndromes and contrasting floral displays. Here, we focus on a hybridizing pair (Rhinanthus minor and R. angustifolius) with strong similarities in flower morphology and pollinators (bumblebees). We examined how ethological isolation changes locally in relation to relative Rhinanthus frequencies, spatial configurations, and pollinator assemblages. Interestingly, floral divergence based on adaptation to different pollinators is unlikely in Rhinanthus: no relationship was found between floral isolation and the local pollinator assemblage. In contrast, species frequency and spatial arrangement strongly influenced bumblebee behavior, ethological isolation, and thus potentially hybrid formation. When both Rhinanthus were pre...

为阐明传粉者在被子植物（angiosperms）多样化过程中所扮演的角色，需聚焦于植物分化早期阶段花隔离（floral isolation）的局域变异模式。目前已开展的少数研究通常采用具有明显传粉综合征（pollination syndromes）和显著花展示差异的物种对。本研究聚焦于一对杂交物种（小鼻花Rhinanthus minor与窄叶鼻花R. angustifolius），二者在花形态及传粉者（熊蜂bumblebees）方面具有高度相似性。我们探究了行为隔离（ethological isolation）的局域变化与鼻花属物种相对频率、空间配置及传粉者群落（pollinator assemblages）之间的关联。有趣的是，鼻花属物种中基于不同传粉者适应的花分化可能性较低：花隔离与局域传粉者群落之间未发现显著关联。相反，物种频率与空间排布显著影响熊蜂行为、行为隔离，进而可能影响杂交后代的形成。当两种鼻花属物种均被预...