Paternal absence can significantly alter bio-behavioural development in many biparental species. This effect has generally been demonstrated by comparing the development of offspring reared under biparental care with those reared by a single mother. However, studies employing this design conflate two significant modifications to early-life experience: removal of father-specific qualities and the general reduction of offspring-directed care. In the socially monogamous prairie vole (Microtus ochrogaster), the experience of paternal absence without substitution during development inhibits partner preference formation in adulthood, a hallmark of social monogamy, in females and males. Employing alloparents as substitutes for fathers, our previous work demonstrated that paternal absence affects pair-bond formation in female offspring via reduced quantity of care, although it affects pair-bond formation in male offspring by means of a missing paternal quality (or qualities). Here, we present evidence that paternal absence (with and without alloparental substitution) may alter the ontogeny of neural oxytocin receptor (OXTR) and/or vasopressin 1a receptor (AVPR1a) distribution in male and female prairie voles. Compared to biparentally reared controls (BPC), male offspring reared in mother only (MON) and maternal-plus-alloparental (MPA) conditions show lower densities of OXTR in the central amygdala; and MPA males show lower densities of OXTR in the caudate putamen and nucleus accumbens. Early-life experience was not associated with differences in AVPR1a density in males. However, MON and MPA females show greater densities of AVPR1a in the medial amygdala than BPC; and MPA females show greater densities of AVPR1a in the ventromedial nucleus of the hypothalamus. We also demonstrate with corticosterone concentrations that MON and MPA offspring are not differentially susceptible to a stressor (ie, social isolation) than BPC offspring. These findings suggest that paternal absence, although likely not a salient early-life stressor, has neuroendocrine consequences for offspring, some of which may affect partner preference formation.

中文翻译：

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早期育儿结构的组成变化改变草原田鼠（Microtus ochrogaster）中催产素和加压素1a受体的发育

父系缺失可以显着改变许多双亲物种的生物行为发育。这种效应通常通过比较双亲抚养与单亲抚养的后代的发育来证明。然而，采用这种设计的研究将早期生活经历的两个重大修改混为一谈：消除父亲特有的品质和普遍减少以后代为导向的护理。在社会一夫一妻制的草原田鼠（Microtus ochrogaster)，在发育过程中没有替代父亲的经历抑制了成年期伴侣偏好的形成，这是女性和男性社会一夫一妻制的标志。使用同种异体父母作为父亲的替代品，我们之前的工作表明，父亲的缺席会通过减少照顾的数量来影响雌性后代的配对键形成，尽管它会通过缺少父亲的质量来影响雄性后代的配对键的形成（或品质）。在这里，我们提出的证据表明，父系缺失（有和没有异亲替代）可能会改变雄性和雌性草原田鼠神经催产素受体（OXTR）和/或加压素1a受体（AVPR1a）分布的个体发育。与双亲饲养的对照 (BPC) 相比，仅在母亲 (MON) 和母体加同种异体 (MPA) 条件下饲养的雄性后代在中央杏仁核中的 OXTR 密度较低；和 MPA 雄性在尾状壳核和伏隔核中的 OXTR 密度较低。早期生活经历与男性 AVPR1a 密度的差异无关。然而，MON 和 MPA 女性在内侧杏仁核中的 AVPR1a 密度高于 BPC；和 MPA 女性在下丘脑腹内侧核中显示出更高的 AVPR1a 密度。我们还用皮质酮浓度证明 MON 和 MPA 后代对压力源（即社会隔离）的敏感性与 BPC 后代没有差异。这些研究结果表明，父亲缺席虽然可能不是一个显着的早期生活压力源，但会对后代产生神经内分泌影响，其中一些可能会影响伴侣偏好的形成。