Van Belle Sarie, Porter Amy, Fernandez-Duque Eduardo, Di Fiore Anthony
Department of Anthropology, University of Texas at Austin, Austin, Texas.
Department of Anthropology, University of California Davis, Davis, California.
Am J Phys Anthropol. 2018 Dec;167(4):701-712. doi: 10.1002/ajpa.23645. Epub 2018 Oct 1.
Territoriality refers to the consistent defense of an area within the home range (HR) against intrusions of conspecifics. It implies exclusive space use with low degree of overlap among neighboring groups, high site fidelity, specific ranging behavior such as high mobility relative to HR size and frequent visits of territory borders, and monitoring behavior. We examined ranging behavior and use of space to evaluate territoriality in Pithecia aequatorialis in Ecuador.
Between 2005 and 2015, we monitored one main study group continuously and five additional groups for shorter periods (5 months to 2.5 years) at the Tiputini Biodiversity Station, in eastern Ecuador. We scored the location of the study groups at 20 min intervals during, on average, 5 days per month. We estimated saki HRs and core areas (CAs) using the fixed kernel density method (95 and 50%, respectively).
The average HR size was 57 ha and the average CA 14 ha. The degree of overlap between HRs of neighboring groups was low (2-9%). For the main study group, the average overlap between annual HRs was 82%. Mean daily path length across groups was 1,151 m; the defensibility index varied between 1.1 and 2.3 (values >1 are suggestive of territoriality), and the fractional monitoring rate varied between 0.06 and 0.15 (values >0.08 are suggestive of territoriality). Groups did not visit their HR borders (100 m inner buffer) more often than would be expected by chance. Travel speed and directness were comparable between the borders and the centers of groups' HRs.
Our multiyear study suggests that equatorial sakis show low degree of range overlap and high site fidelity and have the potential to be territorial, given their high mobility relative to HR size that allows for frequent border monitoring. Nevertheless, their movement patterns in border areas did not reveal evidence for monitoring behavior.
领域性是指对家域（HR）内某一区域进行持续防御，以抵御同种个体的侵入。这意味着相邻群体间空间使用具有排他性，重叠程度较低，具有较高的地点忠诚度，具有特定的活动范围行为，如相对于家域大小具有较高的移动性以及频繁走访领地边界，还具有监测行为。我们研究了厄瓜多尔赤道僧面猴的活动范围行为和空间利用情况，以评估其领域性。
2005年至2015年间，我们在厄瓜多尔东部的蒂普蒂尼生物多样性站，对一个主要研究群体进行了持续监测，并对另外五个群体进行了较短时间（5个月至2.5年）的监测。我们平均每月有5天，每隔20分钟记录一次研究群体的位置。我们使用固定核密度法（分别为95%和50%）估算了僧面猴的家域和核心区域（CA）。
平均家域大小为57公顷，平均核心区域为14公顷。相邻群体家域之间的重叠程度较低（2 - 9%）。对于主要研究群体，年度家域之间的平均重叠率为82%。各群体的平均每日路径长度为1151米；防御指数在1.1至2.3之间变化（值>1表明具有领域性），部分监测率在0.06至0.15之间变化（值>0.08表明具有领域性）。群体走访其家域边界（100米内缓冲区）的频率并不高于偶然预期。边界处与群体家域中心处的移动速度和直接程度相当。
我们的多年研究表明，赤道僧面猴的活动范围重叠程度较低，地点忠诚度较高，鉴于它们相对于家域大小具有较高的移动性，能够频繁监测边界，因此有可能具有领域性。然而，它们在边界区域的移动模式并未显示出监测行为的证据。
