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Posted: 10 March 2016 by Anne Ashford

Honey guides

Dr Bob Fosbury is an astronomer who has worked on the Hubble Space Telescope amongst many other projects.

But in his spare time he takes remarkable photos including these which show some of the tricks flowers use to entice honeybees and pollinators.
Nectar guides, alternatively called pollen guides and honey guides, are markings or patterns that guide pollinators to their rewards.
These patterns are often invisible to the human eye but all is revealed under ultraviolet light.
Bob told me: “I remember many years ago trying to take UV images of flowers to look for the "bee-guides". I had to use film (actually Polaroid) because of its good UV sensitivity. The most spectacular example of bee-guides that are invisible to us is in the Marsh Marigold.
“It is more difficult now to use digital cameras to carry out this type of experiment because the CCD detectors are coated with a filter that rejects UV light and one has to have access to an adapted camera with this filter removed.
“It is actually possible to show that bee eyes are optimised for UV light by making relatively simple measurements of the diameter of the individual ommatidia [one of the optical units that make up the compound eye of an insect] and comparing this with the radius of curvature of the whole eye.”

For more on bees and beekeeping take a look at Buzz, the newsletter I edit for the Taunton Division of Somerset Beekeepers.