Garner Joseph P, Gaskill Brianna N, Pritchett-Corning Kathleen R
Stanford University, Department of Comparative Medicine, and by courtesy, Department of Psychiatry and Behavioral Sciences, Stanford, California, United States of America.
Charles River, Wilmington, Massachusetts, United States of America.
PLoS One. 2016 May 5;11(5):e0154966. doi: 10.1371/journal.pone.0154966. eCollection 2016.
Alloparenting, a behavior in which individuals other than the actual parents act in a parental role, is seen in many mammals, including house mice. In wild house mice, alloparental care is only seen when familiar sibling females simultaneously immigrate to a male's territory, so in the laboratory, when a pair of unfamiliar female wild mice are mated with a male, alloparenting does not occur because one female will typically be reproductively suppressed. In contrast, laboratory mice are assumed to alloparent regardless of familiarity or relatedness and are therefore routinely trio bred to increase productivity. Empirical evidence supporting the presence of alloparental care in laboratory mice is lacking. Albino and pigmented inbred mice of the strain C57BL/6NCrl (B6) and outbred mice of the stock Crl:CF1 (CF1) were used to investigate alloparenting in laboratory mice since by mating pigmented and albino females with albino males of the same stock or strain, maternal parentage was easily determined. We housed pairs (M:F) or trios (M:2F) of mice in individually ventilated cages containing nesting material and followed reproductive performance for 16 weeks. Females in trios were tested to determine dominance at the start of the experiment, and again 5 days after the birth of a litter to determine if a female's dominance shifted with the birth of pups. Results showed a significant and expected difference in number of offspring produced by B6 and CF1 (p < 0.0001). Pigmented mice nursed and nested with albino pups and vice-versa, confirming empirical observations from many that group nesting and alloparenting occurs in unrelated laboratory mice. When overall production of both individual mice and cages was examined, reproductive suppression was seen in trio cages. Dominance testing with the tube test did not correlate female reproduction with female dominance in a female-female dyad. Due to the reproductive suppression noted in trios, on a per-mouse basis, pair mating outperformed trio mating (p = 0.02) when the measure was weaned pups/female/week. No infanticide was seen in any cages, so the mechanism of reproductive suppression in trio matings may occur before birth.
异亲抚育是指实际父母以外的个体承担起父母角色的一种行为，在包括家鼠在内的许多哺乳动物中都能观察到。在野生家鼠中，只有当熟悉的雌性同胞同时迁入雄性的领地时，才会出现异亲抚育行为。因此在实验室中，当一对陌生的雌性野生小鼠与一只雄性小鼠交配时，异亲抚育行为不会发生，因为通常会有一只雌性的生殖受到抑制。相比之下，实验室小鼠被认为无论是否熟悉或有亲缘关系都会进行异亲抚育，因此常规采用三只一组的繁殖方式来提高繁殖效率。然而，目前缺乏支持实验室小鼠存在异亲抚育行为的实证证据。本研究使用了C57BL/6NCrl品系（B6）的白化和有色近交系小鼠以及Crl:CF1种群（CF1）的远交系小鼠来研究实验室小鼠的异亲抚育行为。由于将有色和白化雌性小鼠与同一种群或品系的白化雄性小鼠交配后，母系血统很容易确定。我们将成对（雄：雌）或三只一组（雄：2雌）的小鼠饲养在单独通风且配有筑巢材料的笼子里，并对其繁殖性能进行了16周的跟踪观察。对三只一组中的雌性小鼠在实验开始时进行了优势地位测试，并在一窝幼崽出生5天后再次进行测试，以确定雌性的优势地位是否随着幼崽的出生而发生变化。结果显示，B6和CF1小鼠所产幼崽数量存在显著且符合预期的差异（p < 0.0001）。有色小鼠会哺育白化幼崽并与它们一起筑巢，反之亦然，这证实了许多人观察到的实证结果，即无关的实验室小鼠会进行群体筑巢和异亲抚育行为。当对单只小鼠和笼子的总体繁殖情况进行检查时，发现三只一组的笼子中存在生殖抑制现象。通过试管测试进行的优势地位测试并未发现雌性之间的二元组中雌性繁殖与雌性优势地位之间存在关联。由于在三只一组的情况下观察到了生殖抑制现象，以每只小鼠为基础衡量时，当衡量标准为断奶幼崽数/雌性/周时，成对交配的繁殖效果优于三只一组的交配（p = 0.02）。在任何笼子中均未观察到杀婴行为，因此三只一组交配中生殖抑制的机制可能在出生前就已发生。
Zotero 插件
