Dioecious plants’ response to insect herbivore chewing vibrations

Chemical defense theory predicts trade-offs between plant growth, defense, and reproduction. Typically, female plants invest in defense whereas males invest in growth. Because insect herbivores have the potential to severely reduce plant fitness, plants have evolved several mechanisms to detect herbivore feeding cues such as saliva and respond with priming chemical defensives. Recent studies found plants also detect herbivore caterpillar footsteps, frass, and bioacoustics vibrations. We investigate if male and female plants respond to insect herbivore bioacoustics differentially.

Using two dioecious plant species, stinging nettle and palmer amaranth, we recorded Spodoptera frugiperda and Spodoptera exigua foliage feeding with a laser vibrometer. Using piezoelectric actuators, we played back the vibration recordings to male and female plants. We quantified above ground biomass, trichome production, leaf chemical defense, and reproductive output, between both male and female plants.