Self-organized spectral adjustment in echolocation sounds within group-flying bats

Self-organized behaviour has been extensively studied in group dynamics in animals, with a strong focus on movement coordination in species like fish and birds. By contrast, far less attention has been paid to vocal interactions within animal groups. Here, we unveil a self-organized vocal behaviour in echolocating bats (Miniopterus fuliginosus), characterized by their adaptive responses to jamming stimuli. Using controlled playback experiments, we identified a mathematical model that describes how bats autonomously adjust their vocal frequencies to avoid signal interference mimicking group echolocation. The model was subsequently extended to simulate a group of bats flying in two-dimensional space. Consistent with previous observations of group-flying bats, the simulation revealed frequency-adjusting behaviour, characterized by an overall increase in frequency differences within the group. Crucially, we demonstrated that this behaviour reduces potential misdetections during echolocation, enhancing group-wide sensory accuracy. These results reveal a mechanism of conflict resolution through self-organized vocal adjustment and establish a parallel with other self-organizing systems in nature. Our findings reveal that this frequency-adjusting behaviour represents a self-organized vocal behaviour that effectively mitigates conflicts within a group, one achieved via simple behavioural rules, as in other types of collective animal behaviour.