Further, you might notice that the flower tilts downward. The pollinator has to be below the flower and point its proboscis upward to insert it in the very long nectar spurs. This nodding flower position with long nectar path is common to hummingbird flowers. Frustrated, he never found the moth. Pollen Rewards Flowers, particularly beetle-pollinated flowers need to provide extra pollen for the food needs of pollinators.
Bees feed on pollen also.
While nectar is mostly sugar and very high-energy food for bees and hummingbirds, pollen is a source of protein, vitamins, and minerals. Fortunately for plants, pollinators feed on pollen but are not fastidious in their own grooming, so they end up depositing at least a few pollen grains on the stigma. Notice the yellow petal that has evolved as a kind of pouch. This pouch traps a fragrance chemical inside that flies find irresistable. The flies land near the opening of the pouch and climb over the edge, falling inside.