Mechanoreceptors in insects: Johnston's organ in Nezara viridula (L) (Pentatomidae, Heteroptera).

Behavioural observations of Nezara viridula suggested that the antennae could be involved in detecting the substrate vibrations important in intraspecific communication of these insects. Therefore the vibrosensitive properties of Johnston's organ, a mechanoreceptor sensitive to the movements of the antennal flagellum relative to pedicel, were investigated. Vibrational stimuli were applied to the proximal flagellar segment where activity in the antennal nerve was recorded via a tapered tungsten electrode inserted into the second antennal segment where Johnston's organ is located. Sensory cells of Johnston's organ scolopidia respond to low frequency substrate vibrations (below 200 Hz). Both fast and slowly adapting receptor cells are present. However, the sensitivity of Johnston's organ to substrate vibrations in Nezara viridula is much lower than that of vibroreceptors in their legs which are known to be involved in intraspecific vibrational communication.