A fundamental issue in the evolution of social behavior is understanding how animals use sensory signals to communicate social information. Senders produce and receivers perceive the same signals, suggesting that species' motor and sensory behaviors co-evolve. Songbirds communicate using complex, species-specific vocalizations (songs) and behaviorally prefer the songs of their own species. Yet, males learn songs and females learn to recognize and evaluate male songs during development, through social experience. Thus, interactions of genetic identity and learning build the behavioral and neural mechanisms of songbird mating communication. Like most mating systems, songbird mating occurs via male-male competition and female choice, meaning that males court many females and females choose the males that produce offspring for the next generation. Because female auditory processing and perception of male song determines which males produce offspring, females drive selection. The aim of this project is to determine species-specific mechanisms that generate female attraction to the acoustic features of male songs. Neural coding and perception of male songs will be compared in females of six species with highly divergent song acoustics and known genetic relatedness. Results will reveal mechanisms whereby social communication evolves. The techniques developed to assess perception and neural function will be shared with other laboratories and used to train young scientists at the postdoctoral, graduate, undergraduate and high school levels. The PI will use the approaches and findings of the project in her education work with high school students, outreach lectures and public interviews.
Comparative studies of mating communication, sensory processing and perception provide a powerful framework for understanding speciation and biodiversity. Songbird species with complex and divergent courtship signals (male songs) and known relatedness present an opportunity to test relationships between male signals and female sensory tuning while controlling for ancestral state. Females rely on perception of song acoustics to assess male quality and choose mates. Thus, perceptual sensitivity to song acoustics and the underlying sensory coding mechanisms are critical to female selection of the males that contribute offspring to the next generation. To examine how female auditory perception and male song acoustics co-evolve, female song preferences, perceptual sensitivities to spectro-temporal sound features, and central auditory coding of songs and synthetic sounds designed to measure spectro-temporal tuning will be quantified in six species. Measures of behavioral and neural auditory sensitivity will be compared to the acoustic features of conspecific and other species? songs. Songs of species in the family Estrildidae are highly divergent and relatedness across species in this family is known. Results will reveal behavioral and neural mechanisms for the matching of female sensory perception and male courtship signals to achieve conspecific communication and mate choice.
