Phenotypic evolutionary response to temporally limited pollinator access in Brassica rapa

Abstract

Plant-pollinator interactions are essential for plant reproductive success and pollinator food supply. However, the ongoing pollinator decline threatens many wild and cultivated flowering plants, urgently requiring studies on its impact on plant populations and their potential evolutionary responses. We combined an experimental evolution with a resurrection approach to test phenotypic evolutive changes in response to artificially limited access of plants to natural pollinators in a common garden setting using Brassica rapa. After six generations, we detected putative adaptive responses to the pollination treatments, including changes in phenology, floral morphology and flower volatile organic compounds, associated with changes in overall attractiveness to hoverflies. Although the generalist plant B. rapa shows ability to rapidly respond to strong limitations to its natural pollinator community, the observed decrease of fitness could threaten the population.