By Lisa Lewis
We all know that potatoes have eyes, but did you know that flowers have ears?
Birds sing, and frogs croak to attract mates. Chimpanzees screech, and dogs bark to sound an alert. We know that plants respond to light, airborne scents and volatile chemicals, and various types of touch, but do they respond to sound? A series of experiments recently conducted both in the laboratory and in the natural outdoor growing environment suggest that plants do indeed “hear” and respond preferentially to sounds.
Most researchers agree that around 85% of plants rely on animal pollinators for reproduction. Plants use the color and shape of their flowers as well as food rewards in the form of nectar and pollen to attract pollinators. But increasing nectar production, particularly the sugar concentration of their nectar, is costly to the plant. By being able to “hear” a pollinator nearby and increasing sugar concentration only then, plants receive a more consistent benefit for the cost outlay.
A series of creative experiments conducted by researchers at The University of Tel Aviv show that plants stepped up the sugar content of their nectar by 12 to 20% within three minutes of “hearing” a recording of a bee buzzing nearby or a recording of a low-frequency sound in the same range as the wings of a bee vibrating. There was no increased sugar in response to a higher frequency sound or silence or when the flowers were covered by little thin glass coverings that blocked airwaves from reaching the flower but not the rest of the plant.
The experiments showed the vibration of the flower petals created by the pollinator’s oscillating wings that caused the plant to up the sugar content of the nectar. It is the petals that serve as the ear for flowering plants. Plants that respond to the buzzing of a bee’s wings with sweeter nectar are visited by pollinators more frequently and for a longer time, resulting in higher reproduction rates for that plant and species of plant. The more we learn about the plants around us, the more awesome we realize they are!
Applications are being accepted for fall Master Gardener classes. If interested, please email firstname.lastname@example.org.
Lewis is a Penn State Master Gardener with the Greene County Extension