Ordered randomness in fly love songs

Abstract

A systematic and painstaking analysis reveals that much of the complexity and variability of the courtship song of male fruit flies can be accounted for by simple rules that relate sensory experience to motor output. See Letter p.233 Males in many animal species produce patterned courtship songs to increase reproductive success with females, so variations in song structure have been seen as detrimental 'noise'. Drosophila melanogaster males use courtship song, generated by wing vibrations, and Mala Murthy and colleagues have studied the patterning of these signals. They find that males adjust the pattern of their songs, constructed of two alternating song modes, according to visual and self-motion sensory inputs. Females are sensitive to these efforts, and change their walking speed according their behavioural state and the song's features. The results contradict a widespread assumption that courtship songs follow a fixed pattern, and establish Drosophila as a promising experimental model to study rapid decision-making in a complex social environment.