By Hamish Johnston
Spring will soon be upon many of us – and for me, nothing evokes the spirit of the season more than a bee buzzing from flower to flower on a warm, sunny afternoon. But I never would have guessed that a bee takes a measure of a flower’s electrical field before it alights.
That’s the claim of biologists at the UK’s University of Bristol, who have shown that bees and plants exchange “information” in the form of electrical charge.
According to Daniel Robert, Heather Whitney and colleagues, flowers tend to accumulate negative charge, whereas bees gain positive charge as they fly. When a bee lands on a flower, some of the charge is neutralized and the flower takes several minutes to charge up again – which the team discovered by placing electrodes on the stems of petunias.
The team also used a charged powder to modify the charge on the surface of several different types of flower and found that the bees were able to distinguish between flowers with different charges.
The biologists speculate that the charge of a flower could tell a bee how long it has been since the flower was last visited by an insect. “This novel communication channel reveals how flowers can potentially inform their pollinators about the honest status of their precious nectar and pollen reserves,” explains Whitney.
Finally, the team devised a learning test for the bees, which had the insects distinguishing between different colours. The researchers found that the creatures learned faster when different colours were accompanied by different electrical fields.