Pollinator-mediated selection

Since many plants rely on pollen vectors, their interactions with them influence floral traits and also favor efficiency since many vectors are searching for floral rewards like pollen and nectar.

Examples of pollinator-mediated selected traits could be those involving the size, shape, color and odor of flowers, corolla tube length and width, size of inflorescence, floral rewards and amount, nectar guides, and phenology.

[3] However, many flowering plants don't display morphology that excludes all pollinators except the one they co-evolved with.

Selection might actually favor some degree of generalization while some flowers can also retain particular traits that allow them to adapt to a certain type of pollinator, but will ultimately be molded by the pollinators that are the most effective and visit the most frequently.

Floral isolation is a consequence of pollinator behavior that reduces inter-lineage pollen transfer, which reduces gene flow and increases the possibility for a transition to different syndromes.

Evolution of multiple pollination syndromes. The columns from left to right are examples of bee, hummingbird and moth-pollination syndromes. Each row shows representatives of the same genus. The top row are columbines ( Ranunculaceae ). The second row are beardtongues (Plantagineaceae) . Third row are catchfly (Caryophylaceae) . The fourth row are morning glories ( Convolvulaceae ). The fifth row are larkspurs (Ranunculaceae) and the last row are gilias ( Polemoniaceae ). Photos by Stickpen, Walter Siegmund, Cstubben, Lionnel, Derek Ramsey, Jebulon, Dinkum, Forest & Kim Starr, S . Zenner, and Jerry Friedman.
Ophrys apifera is an orchid species that has a highly evolved plant-pollinator relationship. This specific species displays sexual deception and floral mimicry that have resulted from the selection pressures of bees.