[click on image to see a larger one]
Rudbeckia fulgida + R. hirta vs white Gazania rigens, visible image:

Rudbeckia fulgida + R. hirta vs white Gazania rigens, reflected UV image:

Rudbeckia fulgida + R. hirta vs white Gazania rigens, simulated bee vision image:

In visible light, all these flowers are rather bright yellow / orange (Rudbeckia) and white (Gazania) to our human eye. But the white Gazania rigens against the Rudbeckia fulgida and R. hirta flowers shows an even more prominent and bright bullseye pattern in reflected UV (only visible to bees and butterflies), as its petals are very, very UV bright (around 370nm) and its center is very UV dark, compared to the other UV reflecting flowers, which makes them clearly even more visible in UV, hence creating an impressive competitive edge in terms of chances for getting pollinated even against those other flowers with UV bullseye pattern - and all this gets nicely visible, also in simulated bee vision.
I have written HERE about it before.
Stay tuned, more will follow on that fascinating subject...