Changing costs of reproduction: age-based differences in reproductive allocation and escape performance in a livebearing fish
Changing costs of reproduction: age-based differences in reproductive allocation and escape performance in a livebearing fish
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DOI：
10.1111/j.1600-0706.2009.17742.x
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发表时间：
2010-01-01
期刊：
影响因子：
3.4
通讯作者：
Tuckfield, R. Cary
中科院分区：
文献类型：
--
作者：
Belk, Mark C.;Tuckfield, R. Cary
生殖价值假说预测，如果剩余生殖价值随着雌性年龄的增长而下降，那么年轻雌性应该将更少的可用能量分配给当前的生育能力，而将更多的能量分配给未来的生殖；然而，老年雌性应该将更多的可用能量分配给当前的生育能力，而不是分配给未来的繁殖（即生存）。我们测试了这一预测，即与年轻雌性相比，老年雌性甘布西亚表现出更高水平的繁殖分配（即繁殖力），因此在怀孕期间经历了更大的逃逸表现（生存成本）下降。与年轻雌性相比，老年雌性的离合器湿质量相对较大，并且在怀孕期间离合器湿质量增加更多。相应地，老年雌性在怀孕过程中逃逸速度显着下降。而年轻女性在整个怀孕期间的逃逸速度没有变化。年老雌性在怀孕早期具有较高的逃逸速度，并且到怀孕末期它们的表现仅下降到年轻雌性的水平。因此，尽管老年雌性表现出更大的性能下降，但它们能够更好地改善性能下降的成本。
The reproductive value hypothesis predicts that if residual reproductive value declines as a female ages, then young females should allocate less of available energy to current fecundity and more to future reproduction; whereas, older females should allocate more of available energy to current fecundity and less to future reproduction (i.e. survival). We test the prediction that older female Gambusia affinis exhibit higher levels of allocation to reproduction (i.e. fecundity) and consequently experience greater decline in escape performance (survival cost) during pregnancy compared to young females. Old females had relatively larger clutch wet masses and clutch wet mass increased more during pregnancy compared to young females. Correspondingly, old females exhibit a significant decline in escape velocity over the course of pregnancy; whereas young females show no change in escape velocity throughout pregnancy. Old females have higher escape velocities early in pregnancy and their performance only declines to about the level of performance of young females by the end of pregnancy. Thus, although old females exhibit a greater decline in performance they are better able to ameliorate the cost of decreased performance.