From wing movements to cues and signals: mechanisms and functions of flight-generated sounds in insects

In insects, the act of flying can produce sounds. Flight sounds result from wingbeat-induced aerodynamic forces, creating acoustic signatures influenced by wing shape, muscle system and body mass, and from several mechanisms, including tymbalation, crepitation, percussion and thoracic vibration, which produce tonal, broadband and ultrasonic emissions. While most studies focus on vibrations produced by perching insects, flight-generated sounds are increasingly recognised as sources of biologically relevant cues and signals in both intra- and inter-specific contexts. Within species, such sounds may provide information during mating swarms, courtship displays or territorial defence interactions, often mediated by frequency modulation and harmonic convergence, especially in Diptera. Across species, flight-generated sounds can contribute to anti-predator strategies through acoustic mimicry and signal exploitation, and may also affect plant-pollinator interactions by influencing floral traits and nectar secretion. Advances in methodology are enabling more precise analysis of insect flight acoustics and associated vibrations, despite challenges posed by behavioural variability and environmental factors. Flight-generated sounds most likely originated as non-signalling byproducts but may, in some cases, have acquired communicative functions under receiver-driven evolutionary pressures. Clarifying when such sounds act as cues, versus when they represent communication signals, remains a key open question. Gaining deeper insights into insect flight acoustics can illuminate the evolutionary mechanisms of information transfer, enrich our understanding of insect behavioural ecology, reveal patterns that contribute to ecosystem diversity, and contribute to non-invasive biodiversity monitoring.