To the human eye, Bidens ferufolia — a species in the sunflower family — has all-yellow petals (left). Bees see the same flower differently: with a bullseye, guiding them to land close to the nectar, held on the nectaries at the center. Humans can distinguish more colors than bees, but bees have a broader range of color vision that extends into the ultraviolet (UV) part of the light spectrum.
The image on the right was shot in UV, and simulated “bee vision” in the center picture with a filter that mimics the UV, blue and green light that bees see. It’s not only color that attracts bees — shimmery petals do, too. Bees can discern color from iridescence, and associate shiny petals with sugar. Our eyes can’t see the iridescence because it’s often in the UV end of the spectrum, which is beyond our vision.
Want to see more about the hidden world of UV and fluorescence photography, and the necessary special lenses, filters and lighting? Check out Klauss Schmitt’s blog: Photography of the Invisible World.