Along with sight and smell, bumblebees can detect
flowers via their electric fields. Scientists already knew that as
bumblebees fly, their wings generate positively charged static
electricity. Flowers usually have a negative charge compared with
the air, a difference that helps carry pollen from a flower to a
bumblebee pollinating it (shown here). Now, lab tests reveal that
bumblebees can learn to distinguish artificial flowers providing a
sweet solution and having a certain pattern of electric field from
similar artificial blossoms dosed with bitter liquids that sport a
distinctly different electric field. These results suggest
that the
insects can also distinguish among natural flowers by their
electric charge, researchers report online
in Science. This matters because a
flower's charge changes temporarily after a bumblebee visits it,
possibly helping other bees avoid a flower that's now low in
pollen. Furthermore, the researchers contend, if bumblebees can
distinguish among blossoms with a lot or a little nectar, the
insects won't be turned off by an entire species of flower after a
few low-reward experiences.