Flowers can hear buzzing bees—and it makes their nectar sweeter

This new study raises another question on Industrialization of agricultural and wilderness areas.  What is the effect of continued low frequency noise on plants?
For crops like corn that are pollinated by wind this might not be an issue, But for other crops this might have negative effects if plants increase nectar sugars expecting pollinators when there are none?
What stresses would be on a plant under continued sounds?

Flowers can hear buzzing bees—and it makes their nectar sweeter
“I’d like people to understand that hearing is not only for ears.”

JANUARY 15, 2019 |  MICHELLE Z. DONAHUE  | nationalgeographic.com

[Excerpt] – Read the full article on nationalgeographic.com

EVEN ON THE quietest days, the world is full of sounds: birds chirping, wind rustling through trees, and insects humming about their business. The ears of both predator and prey are attuned to one another’s presence.

ound is so elemental to life and survival that it prompted Tel Aviv University researcher Lilach Hadany to ask: What if it wasn’t just animals that could sense sound—what if plants could, too? The first experiments to test this hypothesis, published recently on the pre-print server bioRxiv, suggest that in at least one case, plants can hear, and it confers a real evolutionary advantage.

Hadany’s team looked at evening primroses (Oenothera drummondii) and found that within minutes of sensing vibrations from pollinators’ wings, the plants temporarily increased the concentration of sugar in their flowers’ nectar. In effect, the flowers themselves served as ears, picking up the specific frequencies of bees’ wings while tuning out irrelevant sounds like wind.

As an evolutionary theoretician, Hadany says her question was prompted by the realization that sounds are a ubiquitous natural resource—one that plants would be wasting if they didn’t take advantage of it as animals do. If plants had a way of hearing and responding to sound, she figured, it could help them survive and pass on their genetic legacy.

To test the primroses in the lab, Hadany’s team exposed plants to five sound treatments: silence, recordings of a honeybee from four inches away, and computer-generated sounds in low, intermediate, and high frequencies. Plants given the silent treatment—placed under vibration-blocking glass jars—had no significant increase in nectar sugar concentration. The same went for plants exposed to high-frequency (158 to 160 kilohertz) and intermediate-frequency (34 to 35 kilohertz) sounds.

But for plants exposed to playbacks of bee sounds (0.2 to 0.5 kilohertz) and similarly low-frequency sounds (0.05 to 1 kilohertz), the final analysis revealed an unmistakable response. Within three minutes of exposure to these recordings, sugar concentration in the plants increased from between 12 and 17 percent to 20 percent.

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“We have to take into account that flowers have evolved with pollinators for a very long time,” Hadany says. “They are living entities, and they, too, need to survive in the world. It’s important for them to be able to sense their environment—especially if they cannot go anywhere.”

 

This single study has cracked open an entirely new field of scientific research, which Hadany calls phytoacoustics.

 

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