STUDY: Flowers Can Hear Bees Buzzing and Respond By Making Their Nectar Sweeter

January 7, 2021 at 8:38 pm

Flowers are the “ears” of plants, scientists discover! And these ears are particularly tuned in to the sounds of bees!

Plants can hear! And their ears are far prettier than animal ears!

Flowers are more than just pretty decorations for catching the eyes of hungry pollinators. It turns out they also serve as the ears of plants, who suddenly boost the sugar content in their nectar when they hear bees buzzing nearby, according to a new study.

One day, evolutionary biologist Lilach Hadany wondered if plants could hear.

If they could it’d probably have something to do with flowers, she guessed, as pollination is key to plant reproduction.

She was right.

She and a team of researchers from Tel Aviv University decided to experiment with evening primrose  which grows wild around Tel Aviv and whose long bloom time provides substantial quantities of nectar.

In the lab, they exposed the flowers to five different sound treatments: silence, the sound of bees buzzing, and computer-generated sounds in low, medium and high frequencies.

The flowers had no response to the silence or the computer-generated frequencies, they had an almost immediate response to the sound of bees, boosting the sugar content in their nectar by as much as 20% within 3 minutes.

In field trials, while the flowers seemed to tune out other noises, like the wind, they were particularly attuned to the low frequencies emitted by bees and other pollinators.

The temporary boost in sugar content apparently lasted for up to 6 minutes, as pollinators were 9 times more likely to visit a plant that had been previously visited by a pollinator within that time frame.

“We were quite surprised when we found out that it actually worked,” Hadany told National Geographic. “But after repeating it in other situations, in different seasons, and with plants grown both indoors and outdoors, we feel very confident in the result.”

In retrospect, the researchers said it made sense that flowers would be the ears of plants. Their concave, satellite-dish-shape makes them perfect for receiving and amplifying sound waves.

“This specific flower is bowl-shaped, so acoustically speaking, it makes sense that this kind of structure would vibrate and increase the vibration within itself,” study co-author Marine Veits said.

To verify, the team used a laser vibrometer machine to measure the minute movements in the flowers’ petals and saw that the vibrations matched up (resonated) exactly with the wavelengths of the sounds of the bees.

“You immediately see that it works,” Veits says.

Next the researchers want to test whether plants can detect other sounds, like the sound of herbivores mowing down their neighbors perhaps, which might explain how plants send out chemical warnings to each other about potential threats.