Time perception follows Weber's law in Drosophila

The ability to perceive time is essential for adaptive behavior, enabling organisms to respond to change, coordinate actions, and predict future events in dynamic environments and during social interactions. However, its evolutionary origins and underlying neural mechanisms remain poorly understood. Here, we demonstrate that the fruit fly, Drosophila melanogaster, can perceive time intervals ranging from sub-second to a few seconds and use them to predict the location of potential food sources. Using a behavioral paradigm in which flies learn to associate temporal patterns of sound with food rewards, we show that their ability to discriminate between two time intervals depends on the ratio of their durations rather than their absolute difference. This proportional relationship follows Webers law, a fundamental principle of sensory discrimination. Moreover, flies can generalize learned temporal rules to novel stimuli and across sensory modalities, suggesting they form an abstract representation of time. Finally, we identify the mushroom body as a critical neural circuit for temporal learning. These findings reveal unexpected timing capabilities in Drosophila, providing new insights into the evolutionary origin of temporal cognition and establishing Drosophila as a genetically tractable model for investigating the neural basis of time perception.