A central component of an organism’s fitness is its ability to successfully reproduce. This includes finding a potential mate and successful mating. For plants, movement of pollen from an anther to a conspecific stigma is essential for successful reproduction, but directly tracking movement of individual pollen grains heretofore has been impossible (with the exception of those species of orchids and milkweeds whose pollen comes in large packages (pollinia)). Knowing how pollen move around, whether or not they successfully fertilize ovules, is also central to understanding the evolution and ecology of flowering plants (angiosperms) and floral traits.
Plant-pollinator interactions are often considered to be the textbook example of co-evolution. But specialised interactions between plants and pollinators are the exception, not the rule. Plants tend to be visited by many different putative pollinator species, and pollinating insects tend to visit many plant hosts. This means that diffuse co-evolution is a much more likely driver of speciation in these communities. So, the standard phylogenetic methods for evaluating co-evolution aren’t applicable in most plant-pollinator interactions. Also, many plant-pollinator communities involve insect species for which we do not yet have fully resolved phylogenies. Continue reading →