Floral complexity can help maintain plant diversity by inducing pollinator specialization

The global decline in plant biodiversity throughout recent human history has attracted broad scientific attention, as biodiversity plays a key role in promoting a productive ecosystem. Pollination is a major factor in plant survival but carries an additional cost for locally rare plant species: they are likely to receive high levels of incompatible pollen that does not contribute to reproduction and can even impair seed production. Therefore, floral traits that diminish the risk of incompatible pollen receipt may be favoured by natural selection. We developed a theoretical framework to explore the influence of floral morphological complexity on competition for pollinator services between self-incompatible simultaneously flowering plant species. We show that when a rare plant species is morphologically complex, it may persist in competition with a more common species. Synthesis. The results show that, through its influence on pollinator foraging behaviour, complex floral morphology can contribute to the maintenance of plant diversity.