Data from: The evolution of floral signals in relation to range overlap in a clade of California Jewelflowers (Streptanthus s.l.)

Because of their function as reproductive signals in plants, floral traits experience distinct selective pressures related to their role in speciation, reinforcement, and prolonged coexistence with close relatives. However, few studies have investigated whether population-level processes translate into detectable signatures at the macroevolutionary scale. Here, we ask whether patterns of floral trait evolution and range overlap across a clade of California Jewelflowers reflect processes hypothesized to shape floral signal differentiation at the population level. We found a pattern of divergence in floral scent composition across the clade such that close relatives had highly disparate floral scents given their age. Accounting for range overlap with close relatives explained additional variation in floral scent over time, with sympatric species pairs having diverged more than allopatric species pairs given their age. However, three other floral traits (flower size, scent complexity, and flower color) did not fit these patterns, failing to deviate from a null Brownian Motion model of evolution. Together, our results suggest that selection for divergence among close relatives in the composition of floral scents may play a key, sustained role in mediating speciation and coexistence dynamics across this group, and that signatures of these dynamics may persist at the macroevolutionary scale.花部性状作为植物的生殖信号，会受到与物种形成、生殖增强及与近缘类群长期共存相关的差异化选择压力作用。然而，鲜有研究探讨种群水平的过程是否会在宏进化尺度上留下可检测的演化印记。本研究旨在探究加州珠宝花（California Jewelflowers）所属演化支的花部性状演化模式与分布重叠格局，是否契合学界假说中可在种群水平塑造花部信号分化的演化过程。本研究发现该演化支的花香成分呈现分化模式：在考虑类群分化时间的前提下，近缘类群的花香组成存在显著差异。纳入近缘类群的分布重叠因素后，可进一步解释花香组成随时间产生的变异：在考虑分化时间的前提下，同域（sympatric）物种类对的花香分化程度显著高于异域（allopatric）物种类对。但其余三类花部性状——花大小、花香复杂度与花色——均未符合上述模式，其演化并未偏离零假设的布朗运动（Brownian Motion）演化模型。综合来看，本研究结果表明：针对近缘类群花香组成分化的选择，可能在该类群的物种形成与共存动态调控中发挥关键且持久的作用，且这类动态的演化印记可在宏进化尺度上得以留存。