Mechanisms of Defensive Stridulation in the Bushcricket Mygalopsis marki Bailey (Copiphorini, Tettigoniidae)

The copiphorine tettigoniid Mygalopsis marki uses two acoustic defensive displays which are quite distinct from the tegminal stridulatory mechanism. Both adults and nymphs utilise a stridulation produced within the head capsule. Observation and simple experiment reveal that this sound is produced in conjunction with the passage of air into the buccal cavity. There are large trachea beneath the frons which may be associated as amplifiers of these noises. The hind wings of the adults have small downward projecting spines set in open membranous areas of the wings. When the insect is excited, these spines engage a highly specialised area of the cuticle on the dorsal terga. The production of the noise requires only slight movement of the abdomen. Its role in defense is discussed.