These yucca flowers are blooming near the cliff in our yard. Yucca flowers are only pollinated by the yucca moth, which also depends on the yucca plant as a food source for its larvae. Is there an advantage for the yucca plant to only be pollinated by this one kind of moth?
In a desert climate, yucca plants tend to be very widely scattered. If they had to rely on casual pollinators going from flower to flower, the chances of actually being pollinated with pollen from another yucca would be very small. The adaptation to a single pollinator means a much better chance of successful pollination. This strategy is used by quite a few plants to increase their odds for successful reproduction.