While not possessing ears, the evening primrose can still detect certain sound frequencies that vibrate their petals.
According to findings published by scientists at Tel Aviv University in 2018, the evolutionary mechanism developed within Oenothera drummondii to recognize the buzzing of bees, which serve as the blossom’s principal pollinators. Reacting to the audible stimuli, the evening primrose can produce sugary-nectar in under four minutes to attract the insects.
Other plants have similar abilities. A 2014 study from researchers at the University of Missouri showed that, when exposed to the audio recordings of a caterpillar chewing a leaf, an Arabidopsis plant would discharge higher doses of mustard oil, meant to drive away attacking invertebrates.