Senescence impacts reproduction and maternal investment in bottlenose dolphins
Senescence impacts reproduction and maternal investment in bottlenose dolphins
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DOI：
10.1098/rspb.2018.1123
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发表时间：
2018-07-25
影响因子：
4.7
通讯作者：
Mann, Janet
中科院分区：
文献类型：
--
作者：
Karniski, Caitlin;Krzyszczyk, Ewa;Mann, Janet
生殖衰老在许多哺乳动物物种中都很明显。一个新兴的观点认为生殖衰老的组成部分，作为进化上不同的现象：生育力衰老和母亲效应衰老。生育力衰老被认为是生殖生理的老化，而母体效应衰老则是指由于年龄的增长，提供和养育存活后代的能力下降。两者都导致子宫内的生殖失败，使得在野生环境中产前很难区分两者。我们调查了这两个组成部分;通过三个参数：小牛存活率、出生间隔（IBI）和哺乳期，在具有长期母体护理的长寿哺乳动物中。我们提供了明确的证据，生殖衰老的野生种群的海豚（Tursiops aduncus）使用34年的纵向数据229成年女性和562小牛。小牛的存活率随着母亲年龄的增长而下降，年龄较大的母亲的小牛的存活率低于出生顺序的预测，这表明母亲效应衰老。哺乳期和IBIs增加与母亲的年龄，和IBIs增加，而不管小牛死亡率，表明生育力和母亲效应衰老之间的相互作用。存活到断奶的小牛，最后出生的小牛断奶晚于早期出生的小牛，终端投资的证据，一种缓解策略，降低生殖价值所造成的生殖衰老的组成部分。
Reproductive senescence is evident across many mammalian species. An emerging perspective considers components of reproductive senescence as evolutionarily distinct phenomena: fertility senescence and maternal-effect senescence. While fertility senescence is regarded as the ageing of reproductive physiology, maternal-effect senescence pertains to the declining capacity to provision and rear surviving offspring due to age. Both contribute to reproductive failure in utero making it difficult to differentiate between the two prenatally in the wild. We investigated both component; in a long-lived mammal with prolonged maternal care through three parameters: calf survival, interbirth interval (IBI) and lactation period. We provide clear evidence for reproductive senescence in a wild population of bottlenose dolphins (Tursiops aduncus) using 34-years of longitudinal data on 229 adult females and 562 calves. Calf survival decreased with maternal age, and calves with older mothers had lower survival than predicted by birth order, suggesting maternal-effect senescence. Both lactation period and IBIs increased with maternal age, and IBIs increased regardless of calf mortality, indicating interactions between fertility and maternal-effect senescence. Of calves that survived to weaning, last-born calves weaned later than earlier-born calves, evidence of terminal investment, a mitigating strategy given reduced reproductive value caused by either components of reproductive senescence.