Effects of maternal social stability on female reproductive success in wild house mice (Mus musculus domesticus)

孕期和出生后早期的母体环境可以影响后代的发育。对家鼠的大量实验室研究表明，社会不稳定会导致慢性压力，这可能会对婴儿产生不利影响，或使婴儿发育适应不利的环境条件。相比之下，据报道，如果雌性通过增加断奶成功率和提高后代质量来与同性伴侣建立稳定的社会纽带，婴儿的健康就会受益，这表明断奶时体重更高。与此同时，雌性之间的性内竞争导致了群居雌性的生殖扭曲和生殖抑制。因此，在自然条件和相当复杂的社会环境中，不清楚女儿在多大程度上受益于母亲的社会稳定(高社会稳定)或遭受其母亲的社会不稳定环境(低社会稳定)，以及这种影响是否受到激素的调节。目前的研究将在一群在繁殖竞争中经历季节性变化的自由生活的家鼠中测试这一假设，即母亲的社会环境对她女儿的生殖成功具有长期的影响。我们将利用过去14年来仔细研究的野生家鼠种群。通过对自由生活的个体家鼠进行社会网络监测获得的行为数据将与生活史数据以及通过分析动物毛发中包含的激素获得的长期类固醇激素谱相结合。我们将使用这组数据来检验三个主要假设：(I)母亲在怀孕和哺乳期间的社会稳定性与女儿一生的生育成功呈正相关；(Ii)对于母亲来说，社会不稳定是一种长期的压力状况，可以通过类固醇激素输出的变化影响她的女儿S的生育成功；(Iii)假设母亲的社会不稳定与糖皮质激素(应激激素)的产生增加有关，我们预测对女儿的生理激素谱产生调节作用。

Offspring development can be shaped by the maternal environment during gestation and the early postnatal period. Numerous laboratory studies on house mice suggest that social instability induces chronic stress, which can have detrimental effects on infants or shape infant development towards adverse environmental conditions. In contrast, fitness benefits for infants have been reported if females established stable social bonds to same-sex partners through increased weaning success and enhanced offspring quality as indicated by higher weight at weaning. At the same time, intra-sexual competition among females results in reproductive skew and reproductive suppression of group living females. Thus, under natural conditions and in a rather complex social environment it is unclear to what extent daughters benefit from a socially stable (high social stability) or suffer from a socially instable environment (low social stability) of their mothers, and whether such effects are modulated by hormones. The current study will test the hypothesis that a mothers social environment has long-lasting effects on her daughters´ reproductive success in a free-living population of house mice that undergoes seasonal variation in reproductive competition. We will use access to a population of wild house mice that has been carefully studied over the past 14 years. Behavioral data obtained by social network monitoring of the free-living individual house mice will be combined with life history data as well as with long-term steroid hormone profiles obtained by analyzing the hormones incorporated in the animals´ hair. We will use this data set to test three main hypotheses: (I) Maternal social stability during gestation and nursing positively correlates with the lifetime reproductive success of daughters; (II) social instability is a chronically stressful situation for a mother that can influence her daughter´s reproduction success mediated by alterations in steroid hormone output; (III) provided that maternal social instability is associated with elevated glucocorticoid hormone production (stress hormones), we predict modulating effects on their daughters´ physiological hormone profile.