Introduction
The effects of sound on plant growth and other traits have
been recognized for decades, but the ecological significance
of these responses is unclear. While plant responses
to wind and touch have been examined and have clear
adaptive significance (Chehab et al. 2009), plant responses
to acoustic energy have largely been studied in the absence
of an ecological context. For example, there is a long tradition
of exposing plants to musical sound (Klein and Edsall
1965; Telewski 2006; Jeong et al. 2004). Although music
influences growth and germination in some plants, music
contains such a wide range of frequencies, amplitudes and
fine-temporal patterns that its usefulness as an experimental
stimulus is limited. More systematic studies have found
that some frequencies have a greater influence than others
(Telewski 2006). For example, young roots of corn grow
towards the source of continuous tones, transmitted as airborne
or waterborne sound, and respond optimally to frequencies
of 200–300 Hz (Gagliano et al. 2012a). While
these studies bring us a step closer to being able to link
plant responses to acoustic energy to ecologically relevant
sound sources, the experimental stimuli still remain far
removed from those produced by natural sources of acoustic
energy in the plant’s environment.
One of the most relevant sources of acoustic energy in
the immediate environment of a plant is the rich community
of plant-associated arthropods, including herbivores,
predators, and parasitoids (Cocroft and Rodriguez 2005).