The Character of Larval Sounds of the Japanese Pine Sawyer, Monochamus alternatus HOPE

Studies were carried out on the sounds produced by Japanese pine sawyer larvae. The duration of sounds alternating with silent phases, intervals between sound-units, and wave form and intensities of sound-units were studied, and larval sound producing behavior was observed. The duration of one continual sound production did not exceed five min and shortened with the progression of larval development. Intervals between two sound-units were approximately two sec and nearly constant throughout larval development. Sound-units lasted nearly 0.04sec in length and consisted of more than 10 wave trains which were around 0.001sec in length. The intensity of sound pressure exceeded 40dB and the sounds were clearly audible at more than 15m from the sound source in a pine stand during good weather conditions. Larvae were also observed revealed to produce sound from a posture contacting mandibles with gallery walls.