Male body size, dominance rank and strategic use of aggression in a group-living mammal
Male body size, dominance rank and strategic use of aggression in a group-living mammal
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DOI：
10.1016/j.anbehav.2019.03.011
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发表时间：
2019-05
期刊：
影响因子：
2.5
通讯作者：
Edward Wright;J. Galbany;S. McFarlin;Eric Ndayishimiye;T. Stoinski;M. Robbins
中科院分区：
文献类型：
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作者：
Edward Wright;J. Galbany;S. McFarlin;Eric Ndayishimiye;T. Stoinski;M. Robbins
在许多动物物种中，体型是雄性战斗力和繁殖成功的关键决定因素，但在群体生活的动物中，这些变量之间的关系很少被研究，在群体生活的动物中，体型往往与优势等级相关。对生活在多雌群中的26只野生成年雄性山地大猩猩(Gorilla Beringeiberingei)的体型(冠高、背宽和体长)、优势度、雄性终身期长短、成年雌性数量与攻击模式之间的关系进行了研究。冠高和背宽(变量高度相关并合并成冠背评分)的综合测量，而不是体长，与优势度、阿尔法男性任期长度和每组成年女性的数量显著相关。在七组中的六组中，阿尔法男性的冠背得分最高，并且在大多数二元组中，冠背得分越高的男性排名越高。在等级接近的雄性之间，攻击性竞争的频率(和交配日的强度)更高。此外，当发起者比接受者大时，攻击行为发生的频率更高。我们的结果表明，除了体型以外的其他因素可能会影响优势度，但体型较大有助于雄性获得并保持较高的优势度，可能导致更大的繁殖成功。进一步研究雄性-雄性竞争的时机和强度如何影响第二性征、身体状况和生存之间的投资之间的生活史权衡，可能会解释物种内和物种间终生生殖成功的差异。
Body size is a key determinant of male fighting ability and reproductive success in many animal species, but relationships between these variables have only rarely been examined in group-living animals in which body size often correlates with dominance rank. We examined the relationships between body size (crest height, back breadth and body length), dominance rank, alpha male tenure length, number of adult females and patterns of aggression in 26 wild adult male mountain gorillas,Gorilla beringeiberingei, living in multimale groups. A composite measure combining crest height and back breadth (variables were highly correlated and combined into a crest–back score), but not body length, significantly correlated with dominance rank, alpha male tenure length and number of adult females per group. The alpha male had the largest crest–back score in six of the seven groups, and in the majority of dyads the male with the higher crest–back score was higher ranking. The frequency (and intensity on mating days) of aggressive contests was higher between males close in rank. Additionally, aggression occurred more frequently when the initiator was larger than the recipient. Our results suggest that factors other than body size are likely to influence dominance rank, but large size helps males attain and retain high dominance rank, probably leading to greater reproductive success. Further studies on how the timing and intensity of male–male competition influences life history trade-offs between investment in secondary sexual characteristics, body condition and survival may explain variance in lifetime reproductive success within and between species.