Bees with evening primrose

I Hear you, Loud and Clear

Ears. We hear things even when we are not listening.  Our days are filled with noises that we need not consciously register. The hum of traffic, the wind, the spinning of a fan on a hot day. These kinds of sounds do not motivate us, or compel us to change our behaviours. They are so common, so insignificant in our everyday lives that we almost tune them out.

A door slamming, a plate shattering, a panicked scream….these sounds send shockwaves through our bodies. They propel us upwards and outwards, investigating where, what, and why?

Many living things rely on their hearing as we do…using there sense of sound to ascertain whether a situation is safe or should be avoided. Snakes for example, do not have visible ears like we do, their hearing apparatus is connected to their jaws, so they interpret the vibrations they hear to determine whether a situation is favourable.

Similarly, it seems, plants use their ‘ears’ as well. Although they do not have ears as we do, a recent study has shown that a plant that hears a buzzing bee nearby changes its ‘behaviour’, that is, it produces a more concentrated, sugary nectar to attract them.

“It’s important for them to be able to sense their environment—especially if they cannot go anywhere.”
LILACH HADANY, TEL AVIV UNIVERSITY

The study undertaken by Tel Aviv University, examined Evening Primrose flowers, Oenothera drummondii, and found that within mere minutes of sensing bees, the plant temporarily changed the concentration of sugar in their flowers’ nectar. In essence, the flowers themselves were acting as ears, sensing the frequencies produced by a pollinator’s wings, yet tuning out irrelevant sounds. Within just three minutes of exposure to recordings of buzzing bees, the sugar concentration in the plants was seen to increase from between 12 and 17 percent to 20 percent.

Evening Primrose flower
Evening Primrose flower. Source: Healthline

When you think about it, many flowers have a bell like shape, not unalike the anatomy of our ear. This shape allows them to receive and amplify sound waves. This was one of the many observations the team made throughout the research project.

So why would this finding be relevant? Well, just as animals use their senses to detect danger, and find mates, a sweeter nectar may be able to attract more pollinators. The more insects attracted, the more likely the chances of cross pollination. In fact, Lilach Hadany and her team found that in their observations it was evident that a pollinator was more attracted to plants another pollinator had visited within the 6 minutes prior.

“We were quite surprised when we found out that it actually worked,” Hadany says. “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.”

Source: Steve Scott via USDA
Source: Steve Scott via USDA

Hadany, an evolutionary theoretician, began this study after realising that if plants were not able to utilise sound as animals do, they would be at a disadvantage. If plants could in fact listen to, and respond to the sounds they heard, it would help them survive, thrive and reproduce…

And I guess with so many plants around us, that have been surviving and adapting over the years, it seems impossible to think we ever considered they were not able to ‘hear’…

Certainly something interesting to consider in any case.

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Feature Image via Twitter, YorkUScientists

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