Plant–pollinator interactions and threats to pollination : perspectives from the flower to the landscape

Abstract

Animal pollinators have driven the diversification of plants on the earth for more than 100 million years. The mutualism between plants and their pollinators rests on an exchange: food for pollinators and efficient vectoring of sexual reproduction for plants. This relationship has been shaped by many factors during the course of evolution. Competition between pollinators for access to nectar and pollen, and among flowering plants for the attention of pollinators, has influenced the shape, colour, and scent of flowers and the extent to which plants invest in the production of pollen and nectar. While many pollinators are ‘generalists’ and visit a variety of flowering plants to obtain food, close relationships between specific pollinators and plant species have developed throughout the course of evolutionary history. An important issue today, given the widespread concern about wild and managed pollinators, is determining how human activities impact the varied relationships between plants and their insect pollinators.