Scientists at the University of Bristol, Rothamsted Research, and Cardiff University have determined that the electrical charge created by visiting bumblebees stimulates some flowers to release more of their sweet-smelling scent.
The authors posit the trait is expressed in plants to ensure they attract pollinators as opposed to other bugs that might not be as beneficial to the plant's goals: setting fruit!
The electrical charge on a bumblebee—somewhere in the region of 120 picoCoulombs (pC)—is incredibly small but the team found a charge of 600 pC, or about the same as five bee visits, was enough to induce a species of violet petunia, Petunia integrifolia, to markedly release more scent.
Read more about their research
here.