Sound production and hearing in insects

Among the oldest land animals, insects have roamed the planet for over 400 million years. Acoustics plays a vital role in the ecology of many insects across the globe, facilitating mate finding, defence and information transfer. Many insect sounds are readily perceived by human ears, with the sound of singing cicadas or grasshoppers familiar to many. Yet how insects produce sounds, and what they use them for is not always evident, and they might not even be perceptible to human ears. The Belgian painter Erik Pevernagie encouraged acoustic awareness: ‘Let us drop our tin ear and listen to the sounds of the real world veiled beyond our inattention’. His appeal can be elegantly applied to insect bioacoustics, as while singing cicadas epitomise the searing heat of a southern summer to most, there is a vast hidden world of insect sounds, which is both wondrous and complex. Generations of scientists have tasked themselves with uncovering its secrets, with new chapters written still today. Here we will explore and summarise the many fascinating ways insects both produce and perceive sounds, as well as look into how they exploit sound to their benefit in an ecological context. We look to bring together both classic and modern research, while looking to the future to speculate on what the next steps in understanding the acoustic world of insects might be.