August 7, 2018 by glenfoerd
Bee vision is one of the great marvels of the natural world. Their compound eyes allow them to pick up minute details in an incredible range of vision, to respond quickly to movement (much more quickly than humans), and to judge distance and dimension with amazing accuracy. Bees also have three small, single-lensed eyes on top of their head which sense light intensity and help them stabilize in flight.
But what’s truly remarkable is what we’ve come to learn about how bees perceive color, and what it’s revealed about the relationship between pollinators and the plants they pollinate. While human visual perception rests on wavelengths in the range of about 700 to 400 nanometers (red to violet), bees’ sight is shifted toward higher frequencies, running from about 600 to 300 nm. So while bees have trouble seeing red hues, they can easily perceive ultraviolet light, something invisible to humans.
Indeed, this UV perception is essential to their survival. When scientists studied the ultraviolet florescence of flowers—that is, the light plants reflect when exposed to UV light, whether from the sun or an artificial source—they found time and again that many flowers have markings indistinguishable to us, but very obvious to bees. Many flowers have pronounced bullseyes that draw attention to the flower’s center, and the brightly-glowing pollen therein. These UV markings make flowers and their pollen all the more visible to bees, who can quickly hone in on pollen sources thanks to these visual cues.
The science of ultraviolet florescence and perception among plants and animals is still a subject of limited—but growing—research. You can learn more about how plants and pollinators communicate and feed your curiosity about bees at this year’s Philadelphia Honey Festival, taking place September 7-9 at Glen Foerd on the Delaware (Sept. 7), Wyck House (Sept. 8), and Bartram’s Garden (Sept. 9).