White fringed orchids are pollinated by moths. Their cousins, orange fringed orchids, are pollinated by butterflies. Moths are attracted by aroma. Butterflies by color. One result is that white fringed is more successful growing in partly shrubby areas. Since aroma permeates an area, moths can tell when they're getting close even if they can't see the flowers. The butterflies need a clear line of sight to find their nectar.
In this shot, you can see the very long greenish-white spurs that contain nectar. This limits feeding to moths and their long tongues. The moths then go looking for more fringed orchids, because they are also limited by their specialized feeding. This makes for a very deliberate process of pollination. I suspect it also contributes to flower color. White stands out at night when moths are feeding. They use aroma to tell when they are close, but vision to seal the deal.