A tiny electric charge on bees can trigger flowers to emit a fragrance, according to a UK lab study. It appears some plants use this to signal the presence of their flowers to insects to increase their chances of being pollinated.
Bumblebees visiting petunia (Petunia integrifolia) flowers were found to trigger the release of benzaldehyde. Volatile emissions also rose when Clara Montgomery, who carried out the research at the University of Bristol, touched the potted flowers with a charged ball of nylon, but they didn’t when she used an electrically grounded metal rod. Bee antennae were also shown to be responsive to benzaldehyde at those emission levels.
Bumblebees generate a tiny positive charge of around 120 picoCoulombs (pC) as they fly through air. This charge likely helps them gather pollen, which tends to be negatively charged. Bees have antennae and hairs that can sense weak electric fields near flowers and this helps them determine whether a flower was visited recently. The new research suggests that plants also tap into this electrostatic information.