"The last thing a flower wants is to attract a bee and then fail to provide nectar," he said in a prepared statement. Bees quickly learn which flowers are productive and which aren't. The ones that aren't are less likely to get visits and have their pollen spread to other flowers for reproduction. The electrical cues they receive from the flowers may represent a "come back later" signal.
Bees' ability to sense and respond to plants' electrical fields "is a remarkable finding, " says Mark Winston, a biologist at Simon Fraser University in Burnaby, B.C., and the author of a book on bee biology.
It represents another method "by which bees perceive the world around them and it adds another wonderful story that continues to deepen our understanding the co-evolved relationship between bees and flowers," he says.
For 30 years, some researchers have posited that electrostatic charges that can build up on bees play a role in the bees taking up and transporting pollen – a kind of small-scale static cling. They also found that the voltage associated with a flower changes as it's pollinated.
But the experiments by Dr. Robert and colleagues suggest that electricity represents a medium for conveying information between flower and bee before the bee lands.
Previous studies had indicated that bees carry a positive electrical charge with voltages that in some cases can reach as high as 200 volts. They build up the charge as they fly. With their roots in the earth, plants tend to carry a negative charge.