Auditory mechanics in a bush-cricket: direct evidence of dual sound inputs in the pressure difference receiver.

Abstract in brief

• The study examines the auditory system of the bushcricket Copiphora gorgonensis, which has paired eardrums connected by an air-filled tube called the acoustic trachea (AT) that helps process sound with directional sensitivity by reducing the sound velocity and modifying acoustic forces.
• Using advanced imaging techniques like laser Doppler vibrometry and X-ray tomography, researchers measured sound transmission characteristics within the AT, finding that it amplifies sound signals (about 15 dB SPL gain) and slows sound velocity by approximately 25% compared to free field conditions, likely due to heat exchange mechanisms.
• The findings suggest that the reduction in sound velocity in the AT is related to thermal effects, such as heat exchange between the sound waves and the tracheal walls, supporting the idea that multiple sound inputs are integrated to enhance directional hearing in this species.