A trade-off between current and future sex allocation revealed by maternal energy budget in a small mammal.
A trade-off between current and future sex allocation revealed by maternal energy budget in a small mammal.
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小型哺乳动物的母体能量预算揭示了当前和未来性别分配之间的权衡。
DOI：
10.1098/rspb.2010.2654
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发表时间：
2011
期刊：
影响因子：
--
通讯作者：
Rutkowska J
中科院分区：
文献类型：
--
作者：
Rutkowska J
性别分配理论通常假设养育儿子和女儿的适应性成本不同。然而，这种成本的实验确认是稀缺的，潜在的机制很少得到解决。虽然生理成本的最普遍的衡量标准是能量消耗，但只有一项研究将母体能量预算与实验控制的后代性别联系起来。在这里，我们实验测试这在银行田鼠（Myodes glareolus），同时操纵窝的大小和性别比例出生后立即。操作两周后，当母亲处于哺乳高峰期并且同时怀孕时，我们评估了她们的能量预算。我们发现，母亲的食物消耗和每日能量消耗的大小被哺乳的窝。重要的是，后代性别对能量收支的影响取决于同时怀孕的窝仔的特征。具体而言，母亲哺乳所有男性窝，同时怀孕与男性偏见窝的能量消耗最高。这对下一代产生了影响，因为这些母亲同时怀孕的雌性后代的大小受到了影响。我们的研究证明了儿子的成本较高，从而导致对他们的投资较低，并揭示了后代性别在塑造当前和未来母亲投资之间的权衡方面的重要性。
Sex-allocation theories generally assume differential fitness costs of raising sons and daughters. Yet, experimental confirmation of such costs is scarce and potential mechanisms are rarely addressed. While the most universal measure of physiological costs is energy expenditure, only one study has related the maternal energy budget to experimentally controlled offspring sex. Here, we experimentally test this in the bank vole (Myodes glareolus) by simultaneously manipulating the litter's size and sex ratio immediately after birth. Two weeks after manipulation, when mothers were at the peak of lactation and were pregnant with concurrent litters, we assessed their energy budget. We found that maternal food consumption and daily energy expenditure increased with the size of the litters being lactated. Importantly, the effects of offspring sex on energy budget depended on the characteristics of the simultaneously gestating litters. Specifically, the mothers nursing all-male litters and concurrently pregnant with male-biased litters had the highest energy expenditure. These had consequences for the next generation, as size of female offspring from the concurrent pregnancy of these mothers was compromised. Our study attests a higher cost of sons, consequently leading to a lower investment in them, and reveals the significance of offspring sex in moulding the trade-off between current and future maternal investment.