Data from: Natural and anthropogenic influences on the mating system of the common morning glory

Evolutionary biologists remain puzzled by the often dramatic variation of mating strategies within single species. Of particular interest is the extent to which environmental conditions shape patterns of variation of mating system components within mixed mating species, and how widespread anthropogenic manipulations may influence these associations. Here, we address this question in the common morning glory (Ipomoea purpurea) by combining a dataset of floral traits, estimates of the mating system, and relevant environmental factors compiled for 22 populations of this species distributed along a wide range of environments from the Southeast and midwest USA. We identify a disparate set of environmental factors to influence population-level variation in selfing, inbreeding, and flower morphology. While floral traits are primarily associated with climatic variation, the outcrossing rate and inbreeding coefficient are primarily influenced by the level of herbicide resistance. Furthermore, we find that populations with higher levels of herbicide resistance exhibit a stronger correlation between mating system floral traits and mating system estimates (outcrossing rate and inbreeding coefficient). Altogether these results demonstrate the dominant role that herbicide application plays in the determination of I. purpurea’s mating system, and more generally uncover the complex and unforeseen evolutionary consequences of anthropogenic manipulations in natural systems.

进化生物学家始终对单一物种种内交配策略的显著变异现象百思不得其解。其中尤为值得关注的是，环境条件在多大程度上塑造了混合交配物种种内交配系统组分的变异模式，以及人为干预究竟会在多大范围内影响这些关联。针对这一问题，本研究以普通圆叶牵牛（Ipomoea purpurea）为研究对象，整合了该物种22个种群的花部性状数据集、交配系统估计值及相关环境因子数据，这些种群分布于美国东南部至中西部的广泛生境中。研究发现，一系列迥异的环境因子会影响种群水平的自交、近交及花形态变异。其中，花部性状主要与气候变异相关，而异交率与近交系数则主要受除草剂抗性水平的影响。此外，本研究还发现，除草剂抗性水平更高的种群，其交配系统相关花部性状与交配系统估计值（异交率与近交系数）之间的相关性更强。综上，本研究结果证实了除草剂施用在决定圆叶牵牛交配系统过程中的主导作用，同时更广泛地揭示了人为干预自然系统所带来的复杂且始料未及的进化后果。