Detecting an effect of group size on individual responses to neighboring groups in gray-cheeked mangabeys (Lophocebus albigena)

Evolutionary game theory posits that competitive ability affects the initiation of conflicts. When contests occur among groups, competitive ability is generally measured as the size of the group and larger groups are expected to win against smaller groups. However, in some cases, individual participation during intergroup conflicts appears unaffected by competitive ability. To test whether these instances might be due to an unduly strict definition of participation, I re-evaluate the responses of grey-cheeked mangabeys (Lophocebus albigena) to the calls of real and simulated neighboring groups. In contrast with previous analyses, I consider multiple measures of group size, treat movement responses as a continuous variable, and evaluate individual responses (N = 201 focal follows). Males made stronger approaches toward calling neighbors than females, though both sexes tended to retreat from groups that were <500m away and to approach more distant neighbors. Individuals in small groups...

进化博弈论（Evolutionary Game Theory）提出，竞争能力会影响冲突的发起。当群体间发生竞争冲突时，竞争能力通常以群体规模作为衡量标准，且一般认为规模更大的群体将战胜规模更小的群体。然而，在部分情境中，群体间冲突内的个体参与度似乎并不受竞争能力的影响。为验证这类现象是否源于对“参与”的定义过于严苛，本研究重新评估了灰颊白眉猴（Lophocebus albigena）对真实及模拟邻近群体叫声的行为反应。与过往分析不同，本研究采用多种群体规模衡量指标，将移动反应视为连续变量，并对个体反应展开评估（有效样本量为201个焦点取样记录）。相较于雌性，雄性对发出叫声的邻近群体表现出更强的趋近行为；尽管两性均倾向于对距离小于500米的群体采取撤退行为，而对距离更远的群体则选择趋近。处于小型群体中的个体……