Biotremological research using a DIY piezoelectric contact microphone - examples with insects

This study presents a new design of sensor tool to record substrate-borne vibrations produced by insects. We applied a piezo element acting as a contact microphone connected to a digital recorder to detect the signals emitted by insects. A suitable 3D printed microphone box with a mechanism of connection to the substrate or to soft tweezers holding the insect is created. We found that the recordings of the low-frequency signals (up to 20 кHz) were sufficiently good for analysis and, at the same time, a much faster and easier method than the common ones of detecting micro-vibrations using a piezoelectric sensor and, importantly, is incomparably cheaper than using a laser vibrometer. This setup is suitable for the detection and structural description of signals emitted by insects and other arthropods. Oscillograms, spectrograms and audio files of the recorded signals of selected ants (Manica rubida, Latreille, 1802, Messor wasmanni Krausse, 1910, Myrmica ravasinii Finzi, 1923) and Ponera coarctata (Latreille, 1802)), an ant nest beetle (Paussus turcicus I. Frivaldszky von Frivald, 1835), a planthopper (Orosanga japonica (Melichar, 1898)) and a jumping plant louse (Bactericera perrisii Puton, 1876) are provided to demonstrate the effectiveness of the created equipment. The recordings from stridulation in Myrmica ravasinii, Manica rubida, Ponera coarctata and Paussus turcicus and the male call song of Orosanga japonica represent the very first documented signal production for these species. A scheme of the contact microphone and its mode of connection is shown. The research presented will democratise biotremological methods for the needs of integrative taxonomy and behavioural ecology, providing a broader understanding of vibrational signals through an efficient, accessible and operational method for both professional and citizen scientists.