Louder Matthew I M, Voss Henning U, Manna Thomas J, Carryl Sophia S, London Sarah E, Balakrishnan Christopher N, Hauber Mark E
Department of Biology, East Carolina University, Greenville, NC 27858, USA; Department of Psychology, Hunter College and the Graduate Center, City University of New York, NY, NY 10065, USA.
Department of Radiology, Weill Cornell Medical College, NY, NY 10065, USA.
Neurosci Lett. 2016 May 27;622:49-54. doi: 10.1016/j.neulet.2016.04.031. Epub 2016 Apr 16.
In many social animals, early exposure to conspecific stimuli is critical for the development of accurate species recognition. Obligate brood parasitic songbirds, however, forego parental care and young are raised by heterospecific hosts in the absence of conspecific stimuli. Having evolved from non-parasitic, parental ancestors, how brood parasites recognize their own species remains unclear. In parental songbirds (e.g. zebra finch Taeniopygia guttata), the primary and secondary auditory forebrain areas are known to be critical in the differential processing of conspecific vs. heterospecific songs. Here we demonstrate that the same auditory brain regions underlie song discrimination in adult brood parasitic pin-tailed whydahs (Vidua macroura), a close relative of the zebra finch lineage. Similar to zebra finches, whydahs showed stronger behavioral responses during conspecific vs. heterospecific song and tone pips as well as increased neural responses within the auditory forebrain, as measured by both functional magnetic resonance imaging (fMRI) and immediate early gene (IEG) expression. Given parallel behavioral and neuroanatomical patterns of song discrimination, our results suggest that the evolutionary transition to brood parasitism from parental songbirds likely involved an "evolutionary tinkering" of existing proximate mechanisms, rather than the wholesale reworking of the neural substrates of species recognition.
在许多群居动物中，早期接触同种刺激对于准确的物种识别发展至关重要。然而，专性巢寄生鸣禽却放弃亲代抚育，幼鸟在没有同种刺激的情况下由异种宿主抚养长大。从非寄生性的亲代祖先进化而来的巢寄生鸟类如何识别自己的物种仍不清楚。在亲代鸣禽（如斑胸草雀Taeniopygia guttata）中，已知初级和次级听觉前脑区域在同种与异种歌声的差异处理中起关键作用。在此，我们证明成年巢寄生长尾维达鸟（Vidua macroura，斑胸草雀谱系的近亲）的歌声辨别也基于相同的听觉脑区。与斑胸草雀相似，维达鸟在同种与异种歌声及纯音刺激期间表现出更强的行为反应，并且通过功能磁共振成像（fMRI）和即刻早期基因（IEG）表达测量发现，其听觉前脑内的神经反应也增强。鉴于歌声辨别的行为和神经解剖模式相似，我们的结果表明，从亲代鸣禽向巢寄生的进化转变可能涉及对现有近端机制的“进化修补”，而非对物种识别神经基质进行全面重塑。
