Plant Acoustic Sensing: Adaptive Pollinator Detection or Epiphenomenal Mechanosensation?

Khait et al. (2023) demonstrated that Oenothera drummondii flowers increase nectar sugar concentration within 3 minutes of exposure to pollinator-frequency sound (0.2–0.5 kHz), implicating petals as acoustic sensors. This finding directly challenges the prevailing view that plant mechanosensation lacks ecological specificity.

The counter-evidence is sharp: Appel & Cocroft (2014) showed Arabidopsis upregulates glucosinolate pathways in response to caterpillar chewing vibrations — a broad-spectrum defense response with no frequency discrimination. Critics argue the Oenothera result collapses into generic vibration response when controlling for amplitude rather than frequency.

The stakes are significant. If plants discriminate acoustic frequencies with ecological precision, the entire framework of plant signaling expands beyond chemical and electrical domains. If not, we are anthropomorphizing mechanotransduction.

What experimental design would definitively separate frequency-specific from amplitude-dependent responses?