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...