Biology Department, Hofstra University, Hempstead, New York, USA.
School of Biological Sciences, Illinois State University, Normal, Illinois, USA.
Genes Brain Behav. 2024 Oct;23(5):e12907. doi: 10.1111/gbb.12907.
Avian brood parasitism is an evolutionarily derived behavior for which the neurobiological mechanisms are mostly unexplored. We aimed to identify brain regions that have diverged in the brood-parasitic brain using relative transcript abundance of social neuropeptides and receptors. We compared behavioral responses and transcript abundance in three brain regions in the brown-headed cowbird (BHCO), a brood parasite, and a closely related parental species, the red-winged blackbird (RWBL). Females of both species were treated with mesotocin (MT; avian homolog of oxytocin) or saline prior to exposure to nest stimuli. Results reveal that MT promotes approach toward nests with eggs rather than nests with begging nestlings in both species. We also examined relative transcript abundance of the five social neuropeptides and receptors in the brain regions examined: preoptic area (POA), paraventricular nucleus (PVN) and bed nucleus of the stria terminalis (BST). We found that MT-treated cowbirds but not blackbirds exhibited lower transcript abundance for two receptors, corticotropin-releasing factor 2 (CRFR2) and prolactin receptor (PRLR) in BST. Additionally, MT-treated cowbirds had higher PRLR in POA, comparable to those found in blackbirds, regardless of treatment. No other transcripts of interest exhibited significant differences as a result of MT treatment, but we found a significant effect of species in the three regions. Together, these results indicate that POA, PVN, and BST represent neural nodes that have diverged in avian brood parasites and may serve as neural substrates of brood-parasitic behavior.
鸟类巢寄生是一种进化衍生的行为，其神经生物学机制在很大程度上尚未被探索。我们旨在使用社会神经肽和受体的相对转录丰度来识别在巢寄生大脑中分化的脑区。我们比较了棕色头牛鹂（BHCO），一种巢寄生鸟类，和其近亲亲鸟物种红翅黑鹂（RWBL）的三个脑区的行为反应和转录丰度。两种物种的雌性在暴露于巢刺激之前均接受中催产素（MT；催产素的鸟类同源物）或生理盐水处理。结果表明，MT 促进了对有卵巢而不是有乞食雏鸟巢的接近，而无论物种如何，MT 均会促进这种接近。我们还检查了所检查的脑区中五种社会神经肽和受体的相对转录丰度：视前区（POA），室旁核（PVN）和终纹床核（BST）。我们发现，MT 处理的牛鹂但不是黑鹂在 BST 中，两种受体，促肾上腺皮质素释放因子 2（CRFR2）和催乳素受体（PRLR）的转录丰度降低。此外，MT 处理的牛鹂在 POA 中的 PRLR 更高，与黑鹂的 PRLR 相当，而无论处理如何。其他感兴趣的转录本没有因 MT 处理而表现出显着差异，但我们在三个区域都发现了物种的显着影响。综上所述，这些结果表明，POA、PVN 和 BST 代表了在鸟类巢寄生中分化的神经节点，并且可能作为巢寄生行为的神经基质。
