Neural evolution of complex motor behaviors: insights from Drosophila courtship song

The remarkable complexity and diversity of acoustic signals used in social interactions across animal species offers a unique window into the neural basis of behavioral evolution. Among these, the Drosophila courtship song serves as a powerful system for investigating how context-dependent complex motor patterns are encoded and evolve over time. With the aid of advanced tools-including cell-type-specific manipulation and connectomics-researchers are beginning to uncover the circuit architecture responsible for song production. Comparative analyses of homologous neurons across species are further revealing how specific components of the song circuit contribute to the diversification of acoustic signals. In this review, we synthesize recent comparative studies in Drosophila with current knowledge of the courtship song circuit to discuss where and how neural circuits may have evolved to generate species-specific motor patterns and to highlight circuit principles and features that may underlie or shape the evolution of complex motor behaviors.