First high-fidelity scaled 3D-printed models of insect tympanic membrane and acoustic trachea preserving their acoustic function

Abstract

Miniature dual-input hearing in katydids underpins communication and bat evasion, yet its microscale anatomy hinders acoustic studies. With {micro}CT imaging, AI-assisted segmentation and multi-material 3D printed assembly, scaled copies of high-fidelity pinna-tympanum assembly and a complete acoustic trachea of the neotropical katydid Copiphora gorgonensis were fabricated. Flexible TPU membranes reproduce similar tympanal vibrations compared to actual insect and pairing with rigid PLA pinnae mimicked the outer-ear motion, providing ultrasonic gain at 70-110 kHz matching in vivo bat-detection bands. Separately, the pressure mapping of the scaled acoustic trachea confirms the spiracle as a spectral filter and the exponential canal as a 17-21 dB amplifier, in line with simulations, preserving the 1.3 cycle phase shift seen at 23 kHz in living insects. These matching results justify the use of scaled biomimicking replicas as reusable, 3Rs-aligned substitutes for living insect acoustic studies in search bioinspired applications.