Bighorn Ewes Transfer the Costs of Reproduction to Their Lambs
Bighorn Ewes Transfer the Costs of Reproduction to Their Lambs
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DOI：
10.1086/656267
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发表时间：
2010-10-01
影响因子：
2.9
通讯作者：
Festa-Bianchet, Marco
中科院分区：
文献类型：
--
作者：
Martin, Julien G. A.;Festa-Bianchet, Marco
几项关于大型哺乳动物的研究报告称，雌性动物没有直接的生殖成本。个体异质性可能隐藏了生殖的适应性成本，但母亲也可能将一些成本转移给后代。使用的数据442羔羊断奶的146大角羊（绵羊加拿大）母羊在拉姆山，阿尔伯塔，我们研究了如何繁殖的努力与环境和母亲的条件。在夏季，泌乳母羊应该获得足够的质量，以生存的冬天，并支持他们的下一次妊娠，同时护理他们目前的羔羊。我们测量了繁殖的努力，夏季质量增益校正为母亲在6月和母亲在夏季质量增益的羔羊。当种群密度增加时，如果前一年给羔羊断奶，雌性会降低繁殖努力。繁殖努力的减少导致羔羊冬季存活率降低。大角母羊有一个保守的生殖策略，总是有利于自己的身体状况超过他们的羔羊。当资源是有限的，母羊似乎转移到他们的羔羊的生殖成本，预期从更大的相对健身的后果，减少母亲比后代的生存。
Several studies of large mammals report no direct reproductive costs for females. Individual heterogeneity may hide fitness costs of reproduction, but mothers could also transfer some costs to their offspring. Using data on 442 lambs weaned by 146 bighorn sheep (Ovis canadensis) ewes at Ram Mountain, Alberta, we studied how reproductive effort varied with environmental and maternal conditions. During summer, lactating ewes should gain enough mass to survive the winter and to support their next gestation, while nursing their current lamb. We measured reproductive effort as summer mass gain by lambs corrected for maternal mass in June and maternal mass gain during summer. Females lowered their reproductive effort when population density increased and if they had weaned a lamb the previous year. A reduction in reproductive effort led to lower winter survival by lambs. Bighorn ewes have a conservative reproductive tactic and always favor their own body condition over that of their lambs. When resources are limited, ewes appear to transfer reproductive costs to their lambs, as expected from the much greater relative fitness consequences of a reduction in maternal than in offspring survival.