The role of tusks, musth and body size in male-male competition among Asian elephants, Elephas maximus
The role of tusks, musth and body size in male-male competition among Asian elephants, Elephas maximus
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DOI：
10.1016/j.anbehav.2013.09.022
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发表时间：
2013-12-01
期刊：
影响因子：
2.5
通讯作者：
Sukumar, Raman
中科院分区：
文献类型：
--
作者：
Chelliah, Karpagam;Sukumar, Raman
性二形的进化，精心制作的男性特征，似乎是不适应的，可能是由性选择（男性-男性竞争和/或女性配偶选择）驱动的。亚洲象的长牙在性别上是二态的，而且被夸大了，但它在雄性与雄性竞争中的作用还没有确定。我们研究了象牙在建立优势的作用，沿着与其他两个已知的男性男性的信号，即，身体大小和musth（一个临时的生理性提高状态）在印度东北部的亚洲象种群中的有牙和无牙男性的比例相等。在2008-2011年旱季的458个田间日内，我们观察到116种成年（>15岁）雄性之间具有明显优势结果的激动性相互作用。一个广义线性混合效应模型被用来预测获胜的概率作为一个功能的身体大小，象牙拥有和musth状态相对于对手。从这个分析中，出现了三个雄性-雄性信号的层次结构，musth优先于身体大小，身体大小优先于象牙拥有。因此，在这群大象中，拥有象牙在雄性之间的竞争中扮演着相对次要的角色。一个重要的含义是，musth和身体大小比象牙拥有更强的决定优势的因素是，它可以促进人口中的无牙男性在人工选择下对有牙个体的快速进化，这些个体被偷猎象牙。(C)2013年，动物行为研究协会。由爱思唯尔有限公司出版。保留所有权利。
The evolution of sexually dimorphic, elaborate male traits that are seemingly maladaptive may be driven by sexual selection (male-male competition and or female mate choice). Tusk possession in the Asian elephant is sexually dimorphic and exaggerated but its role in male-male competition has not yet been determined. We examined the role of the tusks in establishing dominance along with two other known male-male signals, namely, body size and musth (a temporary physiologically heightened sexual state) in an Asian elephant population in northeastern India with equal proportions of tusked and tuskless males. We observed 116 agonistic interactions with clear dominance outcomes between adult (>15 years) males during 458 field days in the dry season months of 2008-2011. A generalized linear mixed-effects model was used to predict the probability of winning as a function of body size, tusk possession and musth status relative to the opponent. A hierarchy of the three male-male signals emerged from this analysis, with musth overriding body size and body size overriding tusk possession. In this elephant population tusk possession thus plays a relatively minor role in male-male competition. An important implication of musth and body size being stronger determinants of dominance than tusk possession is that it could facilitate rapid evolution of tuskless males in the population under artificial selection against tusked individuals, which are poached for ivory. (C) 2013 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.