Researchers from the University of Bristol have just published a study showing that flowers have yet another method of communicating their desirability to bees besides colors, patterns and scent.
They have electricity.
Plants are usually charged negatively and emit weak electric fields. On their side, bees acquire a positive charge as they fly through the air. No spark is produced as a charged bee approaches a charged flower, but a small electric force builds up that can potentially convey information.
By placing electrodes in the stems of petunias, the researchers showed that when a bee lands, the flower’s potential changes and remains so for several minutes. Could this be a way by which flowers tell bees another bee has recently been visiting? To their surprise, the researchers discovered that bumblebees can detect and distinguish between different floral electric fields.
Also, the researchers found that when bees were given a learning test, they were faster at learning the difference between two colours when electric signals were also available.
How then do bees detect electric fields? This is not yet known, although the researchers speculate that hairy bumblebees bristle up under the electrostatic force, just like one’s hair in front of an old television screen.
Okay, this gets major cool points. (It also gets old fogey points, because how many readers today will actually remember what happens to one’s hair when they get close to an old cathode ray tube television screen?) I love the idea of a bumblebee fuzzing up as it approaches a nectar-laden flower, and have to wonder if they perceive it as a pleasurable sensation. Organisms tend to learn very fast when pleasure is involved. It appears that for bees, “hair-raising” means something completely different than it does for humans and other mammals.
Hat tip to Alma.