Commercial Harvesting Has Driven the Evolution of Camouflage in an Alpine Plant.

Color in nature mediates numerous among and within species interactions, and anthropogenic impacts have long had major influences on the color evolution of wild animals. An under-explored area is commercial harvesting, which in animals can exert a strong selection pressure on various traits, sometimes greater even than natural selection or other human activities. Natural populations of plants that are used by humans have likely also suffered strong pressure from harvesting, yet the potential for evolutionary change induced by humans has received surprisingly little attention. Here, we show that the leaf coloration of a herb used in traditional Chinese medicine (Fritillaria delavayi) varies among populations, with leaves matching their local backgrounds most closely. The degree of background matching correlates with estimates of harvest pressure, with plants being more cryptic in heavily collected populations. In a human search experiment, the time it took participants to find plants was greatly influenced by target concealment. These results point to humans as driving the evolution of camouflage in populations of this species through commercial harvesting, changing the phenotype of wild plants in an unexpected and dramatic way.