Variation in auditory neural activation in response to strain-specific songs in wild and domesticated female Bengalese finches.

Female songbirds identify and prefer conspecific male songs. Songs are an important cue for species discrimination. Bengalese finches are domesticated species and their male songs seem to have evolved as they comprise more complex sequences and tonal sounds than the songs of their wild ancestors, white-rumped munias. Previous research suggested that the degeneration of song functionality for species identification may have been one of the factors that promoted the evolution of song complexity in domestic strains. We hypothesized that female responses to conspecific songs have changed between the two strains: white-rumped munias could distinguish songs of their own species more readily than Bengalese finches. Because the song discrimination is affected by developmental experiences, we used adult female Bengalese finches and white-rumped munias reared with or without exposure to songs of their own strains (i.e., socially-reared or untutored). To evaluate their song discrimination, we quantified zenk-labeled cells in the auditory areas after exposure to song stimuli, either with songs of own strains or those of other strains. Socially-reared white-rumped munias exposed to songs of Bengalese finches showed lesser zenk expression than munias exposed to songs of their own strain. However, there were no significant differences among the groups in Bengalese finches. The result suggests that white-rumped munias could distinguish songs of their own species more strictly than Bengalese finches.