Koch Flávia, Signer Johannes, Kappeler Peter M, Fichtel Claudia
Behavioral Ecology and Sociobiology Unit, German Primate Center, Göttingen, Germany.
Department of Wildlife Science, University of Göttingen, Göttingen, Germany.
Sci Rep. 2016 Jun 22;6:28457. doi: 10.1038/srep28457.
Intergroup competition has an important impact on the survival and fitness of individuals in group-living species. However, factors influencing the probability of winning an encounter are not fully understood. We studied the influence of numerical advantage and location of the encounter on the chances of winning in eight neighboring groups of Verreaux's sifakas (Propithecus verreauxi), in Kirindy Forest, western Madagascar. Intergroup encounters were inferred from spatial data collected via GPS loggers over a period of two years. Location, i.e., the proximity to the respective core area, rather than the numerical advantage of a group in a given encounter, influenced the probability of winning. Accordingly, the high value that resident groups attribute to exclusive and intensively used areas increased their motivation in defending these locations against intruders. Moreover, losers used the encounter area less often than winners within a month after the encounter, suggesting that losing also entails long-term costs. Thus, our results suggest that in gregarious animals the particular circumstances of each encounter, such as the location, can outweigh group characteristics and predict the chances of winning an intergroup encounter.
群体间的竞争对群居物种个体的生存和适应性有着重要影响。然而，影响赢得一场遭遇战概率的因素尚未完全明了。我们在马达加斯加西部基林迪森林中，对八组相邻的维氏冕狐猴（Propithecus verreauxi）群体进行研究，探讨数量优势和遭遇地点对获胜几率的影响。通过GPS记录仪在两年时间里收集的空间数据推断群体间的遭遇情况。在特定遭遇战中，地点，即与各自核心区域的接近程度，而非群体的数量优势，影响了获胜概率。相应地，常驻群体赋予专属且频繁使用区域的高价值增加了它们抵御入侵者保卫这些地点的积极性。此外，在遭遇战发生后的一个月内，失败者比胜利者更少使用遭遇区域，这表明失败也会带来长期代价。因此，我们的研究结果表明，在群居动物中，每次遭遇的具体情况，如地点，可能比群体特征更重要，并能预测群体间遭遇战的获胜几率。
