Aging and improving reproductive success in horses: declining residual reproductive value or just older and wiser?
Aging and improving reproductive success in horses: declining residual reproductive value or just older and wiser?
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DOI：
10.1007/s002650050661
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发表时间：
2000-03-01
影响因子：
2.3
通讯作者：
Minot, EO
中科院分区：
文献类型：
--
作者：
Cameron, EZ;Linklater, WL;Minot, EO
在许多哺乳动物物种中，随着年龄的增长，雌性抚养后代的成功率会提高。剩余生殖价值假说预测，随着母亲年龄的增长，每一个后代对她来说都更有价值，因为现在的后代和未来的后代之间的冲突会减少。因此，随着母亲年龄的增长，她们对后代个体的投入应该会增加。关于剩余生殖价值下降对孕产妇投资影响的经验证据缺乏说服力。年龄较大的母亲可能不会投入更多，但由于经验丰富，可能会更成功，使她们能够更适当地定位自己的投资（目标生殖努力假说）。大多数研究都没有排除这两种假设。母马年龄对生活在新西兰北岛的野马的母系投资有显著影响。年龄较大的母马在抚养小马驹方面更成功，在出生后的前20天里更有保护欲，但之后就不那么勤奋了。大龄母马的总母性投入似乎没有更多，但更适合于马驹存活的最关键时期，在前一年失去马驹的母马中也观察到类似的模式。此外，年长的母马更有可能在连续几年内产下小马驹，这支持了它们在单个后代上的投入少于年轻母马的假设。因此，年龄较大的母亲似乎更容易成功，因为他们的投资更有针对性，因为他们的经验，而不是更多地投资于他们的后代。
In many mammalian species, female success in raising offspring improves as they age. The residual reproductive value hypothesis predicts that each individual offspring will be more valuable to the mother as she ages because there is less conflict between the current and potential future offspring. Therefore, as mothers age, their investment into individual offspring should increase. Empirical evidence for an influence of declining residual reproductive value on maternal investment is unconvincing. Older mothers may not invest more, but may be more successful due to greater experience, allowing them to target their investment more appropriately (targeted reproductive effort hypothesis). Most studies do not preclude either hypothesis. Mare age significantly influenced maternal investment in feral horses living on the North Island of New Zealand. Older mares, that were more successful at raising foals, were more protective for the first 20 days of life, but less diligent thereafter. Total maternal input by older mothers did not seem to be any greater, but was better targeted at the most critical period for foal survival and a similar pattern was observed in mares that had lost a foal in the previous year. In addition, older mothers were more likely to foal in consecutive years, supporting the hypothesis that they are investing less than younger mares in individual offspring. Therefore, older mothers seem to become more successful by targeting their investment better due to experience, not by investing more in their offspring.