Meeting Abstract
In many social animals, early exposure to conspecific stimuli is critical for the development of accurate species recognition. For example, songbirds rely on conspecific ‘tutors’ for appropriate species-specific song development. Obligate brood parasitic birds forego parental care and young are raised by heterospecific hosts. Having evolved from non-parasitic ancestors, how do brood parasites recognize their own species? In non-parasitic parental songbirds (e.g. zebra finch), the primary and secondary auditory forebrain areas are critical in the differential processing of conspecific vs. heterospecific songs. Here we demonstrate that the same auditory brain regions underlie species recognition in adult pin-tailed whydahs (Vidua macroura), a brood parasitic songbird that is a member of the sister family to non-parasitic estrildid finches, including the model species zebra finch (Taeniopygia guttata). Whydahs showed stronger behavioral responses to playbacks of con- vs. heterospecific song playbacks. Using functional magnetic resonance imaging (fMRI), we detected an increase in the mean volume of the blood oxygenation level dependent (BOLD) response to con- vs. heterospecific songs within the auditory forebrain. We also found greater induction of the immediate early gene ZENK within the auditory forebrain following exposure to con- vs heterospecific songs. The evolutionary transition to brood parasitism, therefore, likely involved changes to existing proximate mechanisms–“evolutionary tinkering”–rather than wholesale reworking of neural substrates for species recognition in songbirds.
