Cohort size and the allocation of social effort by female mountain baboons
Cohort size and the allocation of social effort by female mountain baboons
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DOI：
10.1006/anbe.1997.0520
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发表时间：
1997-11-01
期刊：
影响因子：
2.5
通讯作者：
Weingrill, T
中科院分区：
文献类型：
--
作者：
Henzi, SP;Lycett, JE;Weingrill, T
Dunbar (1992, Behav. Ecol. Sociobiol., 33, 35-49) 认为，社交时间的限制限制了萨凡纳狒狒、狒狒、狒狒、狒狒、狒狒、狒狒、狒狒、狒狒、狒狒、狒狒、狒狒、狒狒、狒狒、狒狒、狒狒、狒狒、狒狒和狒狒的数量，第 33, 35-49 页。由于这应该反映在种群结构中，我们在其他地方（Henzi et al. 1997a, Anim. Behav. 53, 525-535）构建了一个基于裂变概率上升的模型，该模型符合观察到的山地狒狒群体规模的分布，P. c. ursinus，位于南非的德拉肯斯堡山脉，它预测，一旦一支队伍的成员超过 23 名（或 8.7 名女性），分裂的可能性就会迅速增加。我们在本文中测试了这一预测。由于邓巴认为，一旦雌性无法进行维持联盟所需的梳理，就会引发裂变，因此我们比较了德拉肯斯堡山脉四支部队的成年雌性的梳理互动。雌性梳理小团体的平均规模达到渐近线，为 7.4 只雌性，因此 8 只或更多雌性的群体中的雌性不再试图为所有其他雌性梳理毛发，平均梳理时间长度随着群体增长到 7.9 只雌性而下降，然后再次增加。这些值与我们的部队增长和裂变模型预测的女性队列规模一致。我们认为，雌性试图为所有其他雌性梳理毛发，并通过更长时间的相互梳理来与少数雌性保持更密切的关系。当梳理所有其他雌性的需求将回合长度缩短到无法进行相互回合的程度时，雌性集团的规模就会受到限制。随着队伍的不断壮大，获得梳理伙伴的机械性困难会导致梳理关系的多样性减少。随着派系变得更加分化，整个女性网络的削弱可能会促进裂变。我们得出的结论是，我们的数据首次在群体内验证了邓巴关于裂变基础机制的假设。在德拉肯斯堡地区，女性联盟没有任何优势，作为一项修正案，我们建议女性离开部队不是为了逃避当地竞争，而是追随与她们有亲密友谊的男性。 (C) 1997 动物行为研究协会。
Dunbar (1992, Behav. Ecol. Sociobiol., 33, 35-49) argued that constraints on social time limited the size to which savannah baboon, Papio cynocephalus, troops in any given population could grow before fissioning. Since this should be reflected in population structure, we have elsewhere (Henzi et al. 1997a, Anim. Behav. 53, 525-535) constructed a model, based on a rising probability of fission, that fits the observed distribution of troop sizes of mountain baboons, P. c. ursinus, in the Drakensberg mountains of South Africa and which predicts that the probability of fission will rapidly increase once a troop has more than 23 members (or 8.7 females). We test this prediction in this paper. Since Dunbar argued that females will drive fission once they cannot engage in the grooming necessary to sustain alliances, we compared the grooming interactions of adult females from four troops in the Drakensberg mountains. The mean female grooming clique size reached an asymptote at 7.4 females, so that females in cohorts of eight or more no longer attempted to groom all other females, and mean grooming bout length declined as the cohort grew to 7.9 females and then increased again. These values are coincident with the female cohort size predicted by our model of troop growth and fission. We argue that females attempt to groom all other females as well as sustain closer relationships with a few females through longer bouts of reciprocated grooming. When the demands of grooming all other females reduce bout length to a point when no reciprocated bouts are possible, female clique size is capped. As a troop continues to grow, the mechanical difficulties involved in gaining access to grooming partners leads to a reduction in the diversity of grooming relationships. This weakening of the total female network, as cliques become more differentiated, is likely to facilitate fission. We conclude that our data provide the first within-population validation of Dunbar's hypothesis concerning the mechanism underpinning fission. In the Drakensberg, where there is no advantage to female coalitions, we propose, as an amendment, that females will leave a troop not to escape local competition, but to follow a male with whom they have a close friendship. (C) 1997 The Association for the Study of Animal Behaviour.