Kurihara Yosuke, Hanya Goro
Primate Research Institute, Kyoto University, Inuyama, Japan,
Japan Society for the Promotion of Science, Chiyoda, Japan,
Folia Primatol (Basel). 2018;89(6):397-414. doi: 10.1159/000493574. Epub 2018 Nov 7.
Behavioral mechanisms of intergroup feeding competition remain unclear, despite its importance as a benefit of group living. Japanese macaques in the coastal and highland forests of Yakushima, Japan, are ideal study subjects because the intensity of intergroup feeding competition differs without phylogenetic effects. We aimed to test whether macaques modify home range use and food patch use in response to the location-specific risk of intergroup encounters. Using behavioral data from 3 groups, we examined the border avoidance and the effects of food patch location on food patch use. All 3 groups used the border less frequently than expected from its area. In the coastal forest characterized by frequent intergroup aggression, the smaller subordinate group, not the larger dominant group, increased the number of co-feeding individuals along the border. This response might reduce the potential costs of intergroup aggression. Feeding duration in one patch, visual scanning, and co-feeding with adult males did not depend on food patch location for the 2 groups. In contrast, the highland group did not modify food patch use along the border owing to the low risk of intergroup encounters. Our results highlight the importance of intergroup hostility as a social factor affecting animal behavior.
尽管群体间觅食竞争作为群居生活的一项益处具有重要意义，但其行为机制仍不明确。日本屋久岛沿海和高地森林中的日本猕猴是理想的研究对象，因为群体间觅食竞争的强度不同，且不存在系统发育效应。我们旨在测试猕猴是否会根据群体间相遇的特定地点风险来改变活动范围的使用和食物斑块的使用。利用来自3个群体的行为数据，我们研究了边界回避以及食物斑块位置对食物斑块使用的影响。所有3个群体使用边界的频率均低于根据其面积预期的频率。在以群体间频繁攻击为特征的沿海森林中，较小的从属群体而非较大的优势群体增加了沿边界共同觅食个体的数量。这种反应可能会降低群体间攻击的潜在成本。对于这2个群体来说，在一个斑块中的进食持续时间、视觉扫描以及与成年雄性共同觅食并不取决于食物斑块的位置。相比之下，高地群体由于群体间相遇的风险较低，并未改变沿边界的食物斑块使用情况。我们的研究结果突出了群体间敌意作为影响动物行为的社会因素的重要性。
