How does pollen-eating favour the division of labour within flowers?
Thousands of species of flowering plants lack nectar and have to use pollen to attract pollinators. Pollen in these species has a dual function: on one hand pollen is the carrier of male gametes and on the other is food consumed by pollinators. In many of these pollen-only species, the male organs (stamens) have been modified to produce two types within the same flower, a phenomenon known to botanists as heteranthery. Using a combination of experimental manipulations and detailed pollinator observations, we have recently demonstrated that this within-flower dimorphism represents the division of labour of pollen into feeding and pollinating functions. In addition, we used theoretical models of the pollination process to show that this functional division of labour can explain the evolutionary maintenance of stamen dimorphism. Our work showed that pollinators can interact in precise ways with the flower, and proved that morphological differences between floral organs result in dramatic c
