Opedal Øystein H, Bolstad Geir H, Hansen Thomas F, Armbruster W Scott, Pélabon Christophe
Centre for Biodiversity Dynamics, Department of Biology, Norwegian University of Science and Technology, NTNU, 7491, Trondheim, Norway.
Norwegian Institute for Nature Research (NINA), NO-7485, Trondheim, Norway.
Evolution. 2017 Jun;71(6):1572-1586. doi: 10.1111/evo.13258. Epub 2017 May 18.
Accurate estimates of trait evolvabilities are central to predicting the short-term evolutionary potential of populations, and hence their ability to adapt to changing environments. We quantify and evaluate the evolvability of herkogamy, the spatial separation of male and female structures in flowers, a key floral trait associated with variation in mating systems. We compiled genetic-variance estimates for herkogamy and related floral traits, computed evolvabilities, and compared these among trait groups and among species differing in their mating systems. When measured in percentage of its own size, the median evolvability of herkogamy was an order of magnitude greater than the evolvability of other floral size measurements, and was generally not strongly constrained by genetic covariance between its components (pistil and stamen lengths). Median evolvabilities were similar across mating systems, with only a tendency toward reduction in highly selfing taxa. We conclude that herkogamy has the potential to evolve rapidly in response to changing environments. This suggests that the extensive variation in herkogamy commonly observed among closely related populations and species may result from rapid adaptive tracking of fitness optima determined by variation in pollinator communities or other selective factors.
准确估计性状的进化潜力对于预测种群的短期进化潜力至关重要，因此也关乎它们适应变化环境的能力。我们对雌雄异位（花中雄性和雌性结构的空间分离）的进化潜力进行了量化和评估，雌雄异位是与交配系统变异相关的一个关键花部性状。我们汇总了雌雄异位及相关花部性状的遗传方差估计值，计算了进化潜力，并在性状组之间以及交配系统不同的物种之间进行了比较。当以自身大小的百分比来衡量时，雌雄异位的中位进化潜力比其他花部大小测量值的进化潜力高一个数量级，并且通常不受其组成部分（雌蕊和雄蕊长度）之间遗传协方差的强烈限制。不同交配系统的中位进化潜力相似，只有在高度自交的类群中有降低的趋势。我们得出结论，雌雄异位有可能随着环境变化而迅速进化。这表明，在密切相关的种群和物种中普遍观察到的雌雄异位的广泛变异，可能是对由传粉者群落变异或其他选择因素所决定的适合度最优值进行快速适应性追踪的结果。
