Tuning of host plants with vibratory songs ofNezara viridulaL(Heteroptera: Pentatomidae)

Abstract

Songs of the southern green stink bug Nezara viridula L, recorded on a non-resonant loudspeaker membrane, reflect frequency characteristics of body vibrations. The song dominant frequency directly depends on the repetition rate of potentials recorded from synchronously contracting muscles that vibrate the abdomen during singing. Spectra of naturally emitted signals recorded on the pronotum of a singing bug or on a plant contain peaks characteristic of plant resonant spectra. The dominant resonant frequency of sound-induced vibrations in bean and other stink bug host plants ranges between 160 and 215 Hz and subdominant peaks do not exceed 600 Hz. There is no correlation between spectral peak positions and recording points on a plant. The dominant resonance peak corresponds to the best frequency sensitivity of N. viridula middle frequency subgenual receptor cell. Subdominant peaks around and below 100 Hz lie close to the dominant frequency of body vibrations during singing and to the range of best frequency sensitivity of low frequency receptor cells. Tuning of plant resonant frequencies with spectral properties of songs and frequency sensitivity of sensory organs is discussed in the context of stink bug substrate-borne communication.