The eye of a honey bee (photo credits).
Flowers look very different to insect pollinators, such as honey bees, compared to what we mammals see.
As the photo on the left shows, bees have compound eyes.
How a bee sees patterns as a result of its compound eyes is wonderfully illustrated at Andy Giger’s B-Eye website.
Like humans, bees can perceive different colors. (This has been know for over 100 years.)
Unlike humans, however, bees can perceive ultraviolet (UV) light.
Thus, the pigments in flower petals that absorb UV light create patterns visible to bees, but that may be invisible to humans. (see photos below)
Flowers in Ultraviolet is a fantastic website that illustrates this in dozens of flowers categorized by plant families.
Plant flavonoids may be the UV-absorbing pigments mostly responsible for the patterns that attract insect pollinators as discussed here.
Taking Photos of Flowers in UV
If you are interested in taking such UV photographs of flowers this is an excellent website to learn how and to see what you need to get started.
For another website on the science and practice of photographing the “invisible” please visit beyondvisible.com.
Flowers Use Several Strategies to Attract Pollinators
It’s clear that some plants have the petal equivalent to “landing lights” at airports to guide airborne pollinators such as bees to the flowers.
Recent research has provided clues regarding how moths key into the scent of a flower, for example.
Bees apparently have pretty short (5 to 10 seconds) memories and, thus, use a combination of visual and chemical (volatiles) cues to locate flowers.
More on this subject can be found in an excellent review (PDF) of how pollinators recognize flowers.
Flowers may also facilitate pollination by using a sort of petal “velcro”.
For further reading, here are some books about bees:
The Buzz about Bees: Biology of a Superorganism
Bottom Line: Many plant species have flower petals containing pigments that absorb UV light, producing patterns presumably visible to – and providing guidance to – insect pollinators, but not to humans (normally, non-pollinators).
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