Age- and state-dependent reproductive effort in male mountain goats, Oreamnos americanus
Age- and state-dependent reproductive effort in male mountain goats, Oreamnos americanus
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DOI：
10.1007/s00265-007-0517-9
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发表时间：
2008-04
影响因子：
2.3
通讯作者：
Julien Mainguy;S. Côté
中科院分区：
文献类型：
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作者：
Julien Mainguy;S. Côté
在哺乳动物一夫多妻交配系统中，雄性的生殖活动主要包括雄性间的竞争和雌性的求偶，这需要付出巨大的躯体代价。因此，男性应根据自己的年龄和状况调整其生殖努力。在这项研究中，我们研究了如何活动预算的雄性山羊（Oreamnos americanus），一个一夫多妻制有蹄类动物，随着年龄的变化，在一个显着的人口在两个时期：（1）夏季1995年至2006年和（2）发情2004年至2006年。然后，我们评估了在发情期间，雄性之间的竞争和求偶行为所花费的时间比例是否受到特定年龄的体重和社会地位的影响。夏季雄性大部分时间用于觅食和休息，随着年龄的增长，休息时间增加，觅食时间减少。在发情期，活动预算发生了明显的变化，因为青少年（1 - 2岁）增加了觅食的时间，而成年人（≥ 3岁）增加了站立和社交互动的时间，牺牲了觅食。在老年，生殖努力要么稳定或略有下降，提供弱支持的“交配策略努力”的假设，预测求偶行为应在壮年男性的高峰。特定的身体质量并没有影响花在男性的男性竞争的时间，但正相关的时间花在求偶行为，提供支持的“个人素质”的假设，预测男性与更多的资源在开始的车辙应该花更多的时间在交配相关的活动。特定的社会地位并不影响生殖努力。存活到黄金年龄，同时每年增加质量，因此应允许男性有蹄类动物获得更大的能力，法院发情的女性。
In mammalian polygynous mating systems, male reproductive effort consists mainly of male–male competition and courting of females, which entail substantial somatic costs. Males are thus expected to adjust their reproductive effort according to their age and condition. In this study, we examined how activity budgets of male mountain goats (Oreamnos americanus), a polygynous ungulate, varied with age in a marked population over two periods: (1) summers 1995–2006 and (2) ruts 2004–2006. We then assessed if the proportions of time spent in male–male competition and courtship behaviors were influenced by age-specific body mass and social rank during the rut. Males spent most of their time foraging and resting during summer, and rested more and foraged less with increasing age. During the rut, pronounced shifts in activity budgets occurred as juveniles (1–2 years) increased time spent foraging, whereas adults (≥3 years) increased standing and time spent in social interactions at the expense of foraging. At old age, reproductive effort either stabilized or decreased slightly, providing weak support for the ‘mating strategy–effort’ hypothesis, predicting that courtship behaviors should peak in prime-aged males. Age-specific body mass did not affect time spent in male–male competition, but was positively related with time spent in courtship behaviors, providing support for the ‘individual quality’ hypothesis, predicting that males with more resources at the start of the rut should spend more time in mating-related activities. Age-specific social rank did not affect reproductive effort. Surviving to prime age while increasing mass each year should thus allow male ungulates to gain greater ability to court estrus females.