Data from: Quantifying hummingbird preference for floral trait combinations: the role of selection on trait interactions in the evolution of pollination syndromes

Darwin recognized the flower's importance for the study of adaptation and emphasized that the flower's functionality reflects the coordinated action of multiple traits. Here we use a multi-trait manipulative approach to quantify the potential role of selection acting on floral trait combinations underlying the divergence and maintenance of three related North American species of Silene (Caryophyllaceae). We artificially generated 48 plant phenotypes corresponding to all combinations of key attractive traits differing among the three Silene species (color, height, inflorescence architecture, flower orientation, and corolla-tube width). We quantified main and interaction effects of trait manipulation on hummingbird visitation preference using experimental arrays. The main effects of floral display height and floral orientation strongly influenced hummingbird visitation, with hummingbirds preferring flowers held high above the ground and vertically to the sky. Hummingbirds also prefer traits in a non-additive manner as multiple two-way and higher-order interaction effects were important predictors of hummingbird visitation. Contemporary trait combinations found in hummingbird pollinated S. virginica are mostly preferred. Our study demonstrates the likelihood of pollination syndromes evolving due to selection on trait combinations and highlights the importance of trait interactions in understanding the evolution of complex adaptations.达尔文早已认识到花在适应性（adaptation）研究中的重要价值，并强调花的功能体现了多个性状的协同作用。本研究采用多性状操控实验方法，量化了作用于花部性状（floral trait）组合的选择压力，在北美3个近缘蝇子草属（Silene，石竹科Caryophyllaceae）物种的分化与维持中所发挥的潜在作用。我们人工生成了48种植物表型（plant phenotype），对应3个蝇子草物种间存在差异的关键吸引性状的全部组合：花色、株高、花序结构、花朝向以及花冠筒宽度。通过实验阵列（experimental array），我们量化了性状操控对蜂鸟访花偏好（hummingbird visitation preference）的主效应与交互效应。花展示高度（floral display height）与花朝向的主效应对蜂鸟访花产生了极强的影响：蜂鸟更偏好生长于地面上方较高位置、且垂直朝向天空的花朵。蜂鸟对性状的偏好呈现非加性模式，多种双向及高阶交互效应均为预测其访花行为的关键指标。当前在蜂鸟传粉的S. virginica中观测到的性状组合，大多为蜂鸟所偏好。本研究证实了传粉综合征（pollination syndrome）可通过作用于性状组合的选择压力演化形成，并凸显了性状交互作用在解析复杂适应性性状演化机制中的核心意义。