Changes in wing resonance in dried preserved crickets

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