Dancing male riflebirds create a dynamic sensory trajectory that guides female choice.

Abstract

Sexual displays often consist of multiple signal components that combine to create dynamic, multisensory "dance" performances.^1,2,3,4,5 However, how signal dynamics guide mate choice remains poorly understood. Deciphering the temporal and rhythmic structure of displays is therefore crucial for understanding their evolution and function. We show that the courtship dances of male Victoria's riflebirds-a bird of paradise endemic to subtropical Australia-involve synchronized visual and acoustic components that begin slowly, subtly accelerate, and culminate in a rapid tempo plateau, during which males flash their yellow gape. All displays that resulted in mating reached this tempo plateau, which was associated with both stronger tempo acceleration and an overall much longer duration of acceleration. Attention holding is likely key to display success, as evidenced by a threshold effect of ∼16 s before any matings occurred, though most displays failed to reach this threshold. We find that higher plateau tempi are clearly associated with mating success, supporting a prevailing hypothesis that female choice generally selects for male performance maxima.^6,7 Although we also find suggestive evidence that stronger tempo acceleration and greater rhythmic variability, but not the rate of gape flashes, improve mating success, these effects were not robust, suggesting potential attention-holding functions.^4,8,9 Our results reveal a unique and rhythmically intricate temporal structure in riflebird mating dances, where males begin with slow, accelerating movements before creating a stimulating grand finale that guides female choice. The sensory trajectory of sexual signals may thus be a core target of mate choice driving the evolution of complex animal dance performances.