In bisexual groups, dominant males occupy the central part of the group, which is advantageous because it is reproductively beneficial. However, high-ranking males do not necessarily monopolize reproductive success, which indicates that low-ranking males increase their reproductive success through alternative mating strategies. To reveal the effectiveness and cost of these strategies employed by group males, it is necessary to clarify the spatial configuration of males and their group, and show how males combine strategies in different situations. This study demonstrates the spatial configuration of male Japanese macaques (Macaca fuscata yakui) and their group when males adopt three mating strategies: mate guarding, sneak mating, and cross-boundary mating (mating with females of another group). High-ranking males tended to perform mate guarding, but they also mated with females in other groups when there were few sexually active females in their group. Low-ranking males performed sneak mating; they remained in the central part of the group to monitor sexually active females and moved toward the periphery for copulation but never completely left the group. In addition, males individually ventured outside the group’s ranging area and succeeded in mating with females of other groups. The cross-boundary mating strategy has the advantage of increasing the number of potential mating partners, which is not present in the other two strategies. However, because of considerable costs and low contribution to mating frequency, this strategy is complementary and is employed when the expectation of mating success in their group is low.

中文翻译：

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屋久岛雄性日本猕猴（Macaca fuscata yakui）采用的空间位置相关交配策略

在双性恋群体中，优势雄性占据群体的中心部分，这是有利的，因为它有利于生殖。然而，高级雄性不一定垄断繁殖成功，这表明低级雄性通过替代交配策略提高了繁殖成功率。为了揭示群体男性采用的这些策略的有效性和成本，有必要阐明男性及其群体的空间配置，并展示男性如何在不同情况下组合策略。本研究展示了雄性日本猕猴 (Macaca fuscata yakui) 及其群体在雄性采取三种交配策略时的空间配置：守卫、偷偷交配和跨界交配（与另一组雌性交配）。高级雄性倾向于保护配偶，但当他们的群体中性活跃的雌性很少时，它们也会与其他群体中的雌性交配。低等级的雄性进行偷偷交配；它们留在群的中心部分监视性活跃的雌性，并移动到外围进行交配，但从未完全离开群。此外，雄性单独冒险走出该群体的范围，并成功地与其他群体的雌性交配。跨界交配策略具有增加潜在交配伙伴数量的优势，这是其他两种策略所不具备的。然而，由于相当大的成本和对交配频率的低贡献，这种策略是互补的，并且在他们的群体中交配成功的期望很低时采用。