Abstract

Aggressive actions are among the most fundamental innate behaviors. Animals across diverse phyla, from sea anemones to mammals, perform antagonistic behaviors, underscoring the ethological importance of such actions. In many animal species, males tend to be more aggressive than females as they engage in male-male disputes over territory and potential mates. However, the molecular and neural basis of the sex-specific level of aggressiveness remains unknown. Using Drosophila as a model, I identified a small number of sexually dimorphic neurons in the male brain that play a critical role in controlling the level of aggressiveness. These neurons express the neuropeptide tachykinin (Tk), the release of which enhances aggression by acting primarily on one of the two Drosophila Tk receptors, Takr86C. Furthermore, I obtained evidence that the activity of these neurons influences “aggressive motivation”, by broadly modulating multiple sensory cues and environmental conditions that affect male aggressiveness. By combining high-throughput behavioral analysis, neuronal imaging and manipulation techniques, and genome editing, I aim to elucidate how complex social behaviors like aggression are controlled by molecules and circuits and to obtain novel insights into the neural components of motivation.