Volatiles that Sound Bad: Sonification of Defensive Chemical Signals from Insects against Insects

Abstract

Defensive chemicals such as volatiles are essential for many insects against the attack of predatory insects, but in the research domain of chemical ecology there remains a need to better understand how intrinsic physicochemical constants of volatiles determine the intra- and interspecific diversification of such compounds produced by prey insects, knowing that many predatory insects primarily rely on chemical cues during foraging. To apprehend and explore the diversity of emitted chemicals as related to the receiver’s perception, here we aim to transform chemical into acoustic signals by a process of sonification, because odours and sounds are similarly perceived in their spatiotemporal dynamics. Since insects often emit a complex mixture of repellents, we prototyped a sonification software to process physicochemical parameters of individual molecules, prior mixing these sonified data by following the chemical profile of specific insect defensive secretions. In a proof of concept, the repellence of insectivorous ants towards single chemicals was compared with the repulsive response of humans towards the auditorily translated signals. Expected outreaches of our ongoing project called 'SonifChem' are, among others, to explore the repulsive and even the attractive bioactivities of chemicals emanating from any (biological) source.