Effect of water availability on volatile-mediated communication between potato plants in response to insect herbivory

Airborne plant communication is a widespread phenomenon in which volatile organic compounds (VOCs) from damaged plants boost herbivore resistance in neighbouring, undamaged plants. Although this form of plant signalling has been reported in more than 30 plant species, there is still a considerable knowledge gap on how abiotic factors (e.g., water availability) alter its outcomes. We performed a greenhouse experiment to test for communication between potato plants (Solanum tuberosum) in response to herbivory by the generalist insect Spodoptera exigua and whether communication was affected by water availability. We paired emitter and receiver potato plants, with half of the emitters damaged by S. exigua larvae and half serving as undamaged controls. Both emitter and receiver plants were subjected to one of two water availability treatments: high (i.e., well-watered) vs. low (i.e., reduced watering) availability, thus effectively teasing apart water availability effects on the emission and...