There was an article several years back in the AOS Bulletin that discussed UV landing sites for insect pollinators. Many of the flowers mentioned had obvious visual indicators for the insects, usually lining up with the callus on the lip of the flower and directing towards the anther cap and ovary.
I've noticed that the bees and wasps have taken an inordinate interest in my pods over the flowers. It may be a hormone related attraction. The bees do not seem to be affected by any UV patterns present in the flowers.