D: Yaël, scientists are claiming that plants can hear. That’s just silly.
Y: If what we mean by hearing is just that a plant detects and responds to sounds, then there’s evidence that you’re wrong, Don.
D: It’s going to take some awfully strong evidence to convince me of that.
Y: OK, in 2019 a team of Israeli scientists published evidence that the evening primrose plant can detect the specific sound vibration frequencies of the buzz of an insect’s wings.
D: And how did they do that?
Y: They divided primrose plants into several groups. The groups exposed to a playback of bee sounds, or to similar low frequency sounds, responded by increasing the sugar content of their nectar within three minutes. Groups exposed to silence, or to high or medium frequency sounds that weren’t like the bee’s buzz, didn’t show this increase.
D: That sounds interesting, but why would a flower increase the sugar content of its nectar?
Y: To reproduce, the primrose plant depends on flying insects to carry its pollen to another plant. It uses the sugary nectar to attract these pollen carriers. It takes lots of energy to make the sugar. If it were sitting around all the time, it would be degraded by microbes or stolen by non-pollinators.
D: I guess I believe you, but please don’t tell me that flowers are the plant’s ears.
Y: Well, umm… the scientists used a sensitive laser device to show that the sound vibration frequencies of buzzing insect sounds caused flowers to vibrate, but that other sound vibration frequencies didn’t. Further study is needed to learn how those vibrations trigger the flower to produce sugary nectar.