Trade-offs in lactation and milk intake by competing siblings in a fluctuating environment
Trade-offs in lactation and milk intake by competing siblings in a fluctuating environment
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DOI：
10.1093/beheco/arw078
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发表时间：
2016-09-01
影响因子：
2.4
通讯作者：
East, Marion L.
中科院分区：
文献类型：
--
作者：
Hofer, Heribert;Benhaiem, Sarah;East, Marion L.
在塞伦盖蒂迁徙猎物的大幅波动大大增加了斑点鬣狗觅食的努力，这降低了护理频率，特别是低级别的女性。母亲通过增加哺乳时间、牛奶质量和数量来部分补偿禁食的幼崽。单胎婴儿比双胎婴儿中的任何一个都能得到更多的牛奶，但双胎婴儿的牛奶摄入量总和却比单胎婴儿多。在双窝中占优势的幼崽成功地利用侵略倾斜牛奶的摄入量在他们favor.Income饲养饲料没有他们的后代出席应调整护理频率和数量和组成的牛奶占主导地位的生态条件，并增加数量或质量的牛奶转移，如果护理访问的频率下降。当一窝产奶量不足时，兄弟姐妹间的竞争会使产奶量偏向优势窝成员。我们量化了牛奶的营养成分和总能量密度，护理回合持续时间，人均牛奶转移（公斤），和牛奶转移率（克/分钟），每一个护理回合在单胞胎和双胞胎的社会食肉动物，斑点鬣狗。在我们的研究人群中，哺乳的能量成本是等级依赖的，特别是高，因为当地猎物丰度的大波动需要长距离觅食，减少护理频率和加强兄弟姐妹的竞争，更频繁地为低级别比高级别的女性。女性增加牛奶总能量密度，驱动脂肪含量，并增加护理回合持续时间的护理频率下降。随着社会地位的下降，牛奶的转移增加。低于中位数的女性也增加了母乳喂养频率下降。牛奶转移是独立的护理频率在女性以上的中位数排名和更高的单胎比幼崽在双窝。占主导地位的兄弟姐妹取得了显着较高的金额和利率的牛奶转移比他们的配对下属同窝出生，这种偏见增加了兄弟姐妹竞争加剧。我们的研究结果显示了生态和社会约束之间的相互作用如何决定牛奶的质量和数量，以及社会上占主导地位的兄弟姐妹如何利用侵略来扭曲牛奶的摄入量。
Large fluctuations in migratory prey in the Serengeti profoundly increase spotted hyena foraging effort, which decreases nursing frequency, particularly by low-ranking females. Mothers partially compensate fasting cubs by increasing nursing bout duration, milk quality, and quantity. Singletons receive more milk than either member of twin litters yet the combined milk intake by twin litters is more than that of singletons. Dominant cubs in twin litters successfully use aggression to skew milk intake in their favor.Income breeders which forage without their offspring in attendance should adjust nursing frequency and the quantity and composition of milk to prevailing ecological conditions, and increase the quantity or quality of milk transferred if the frequency of nursing visits declines. When milk delivery to a litter is insufficient, sibling competition should skew milk consumption in favor of dominant litter members. We quantified milk nutritional composition and gross energy density, nursing bout durations, per capita milk transfer (kg), and milk transfer rate (g/min) per nursing bout in singletons and twins in a social carnivore, the spotted hyena. In our study population, the energetic cost of lactation is rank dependent and particularly high because large fluctuations in local prey abundance necessitate long-distance foraging, reducing nursing frequency and intensifying sibling competition, more frequently for low-ranking than high-ranking females. Females increased milk gross energy density, driven by fat content, and increased nursing bout durations as nursing frequency declined. Milk transfer increased as social status declined. Females below median rank also increased milk transfer as nursing frequency declined. Milk transfer was independent of nursing frequency in females above median rank and higher for singletons than cubs in twin litters. Dominant siblings achieved significantly higher amounts and rates of milk transfer than their paired subordinate littermates; this bias increased as sibling competition intensified. Our results show how the interplay between ecological and social constraints determines the quality and quantity of milk transferred, and how socially dominant siblings use aggression to skew milk intake in their favor.