Changes in wing resonance in dried preserved crickets.

Abstract

Male crickets sing to attract females for mating. Sound is produced by tegminal stridulation, where one wing bears a plectrum and the other a wing vein modified with cuticular teeth. The carrier frequency (f_c ) of the call is dictated by the wing resonance and the rate of tooth strikes. Therefore, the f_c varies across species due to the size of the vibrating membranes on the wings and/or the speed of tooth strikes. But how well is the resonant frequency (f_o ) conserved in dried preserved specimens? This project is designed to investigate the gradual change in cricket wing f_o over time and aims to produce equations that help to predict or recover the original natural frequency of wing vibration in dry-preserved crickets and allies. Using laser Doppler vibrometry, we scanned the wings of living specimens to determine their f_o . The specimens were then preserved, allowing us to continue measuring the wings f_o as they desiccate. We found that after the first week, f_o increases steeply, reaching a plateau and stabilizing for the following months. We go on to propose a model that can be used to recover the original f_c of the wings of preserved Ensifera that use pure tones for communication. Models were corroborated using preserved specimens previously recorded and mounted in dry collections for more than 10 years.