Smith-Aguilar Sandra E, Ramos-Fernández Gabriel, Getz Wayne M
Instituto Politécnico Nacional, Centro Interdisciplinario de Investigación para el Desarrollo Integral Regional Unidad Oaxaca, Santa Cruz Xoxocotlán, Oaxaca, México.
Centro de Ciencias de la Complejidad, Universidad Nacional Autónoma de México, Ciudad de México, México.
PLoS One. 2016 Jun 9;11(6):e0157228. doi: 10.1371/journal.pone.0157228. eCollection 2016.
Ecological and social factors influence individual movement and group membership decisions, which ultimately determine how animal groups adjust their behavior in spatially and temporally heterogeneous environments. The mechanisms behind these behavioral adjustments can be better understood by studying the relationship between association and space use patterns of groups and how these change over time. We examined the socio-spatial patterns of adult individuals in a free-ranging group of spider monkeys (Ateles geoffroyi), a species with high fission-fusion dynamics. Data comprised 4916 subgroup scans collected during 325 days throughout a 20-month period and was used to evaluate changes from fruit-scarce to fruit-abundant periods in individual core-area size, subgroup size and two types of association measures: spatial (core-area overlap) and spatio-temporal (occurrence in the same subgroup) associations. We developed a 3-level analysis framework to distinguish passive associations, where individuals are mostly brought together by resources of common interest, from active association, where individuals actively seek or avoid certain others. Results indicated a more concentrated use of space, increased individual gregariousness and higher spatio-temporal association rates in the fruit-abundant seasons, as is compatible with an increase in passive associations. Nevertheless, results also suggested active associations in all the periods analyzed, although associations differed across seasons. In particular, females seem to actively avoid males, perhaps prompted by an increased probability of random encounters among individuals, resulting from the contraction of individual core areas. Our framework proved useful in investigating the interplay between ecological and social constraints and how these constraints can influence individual ranging and grouping decisions in spider monkeys, and possibly other species with high fission-fusion dynamics.
生态和社会因素会影响个体的移动和群体归属决策，而这些决策最终决定了动物群体如何在空间和时间上异质的环境中调整其行为。通过研究群体的关联与空间利用模式之间的关系以及这些模式如何随时间变化，可以更好地理解这些行为调整背后的机制。我们研究了自由放养的蜘蛛猴（Ateles geoffroyi）群体中成年个体的社会空间模式，蜘蛛猴是一种具有高度裂变融合动态的物种。数据包括在20个月期间的325天内收集的4916次亚群体扫描，用于评估从水果稀缺期到水果丰富期个体核心区域大小、亚群体大小以及两种关联度量的变化：空间关联（核心区域重叠）和时空关联（出现在同一亚群体中）。我们开发了一个三级分析框架，以区分被动关联（个体主要因共同感兴趣的资源而聚集在一起）和主动关联（个体主动寻求或避开某些其他个体）。结果表明，在水果丰富的季节，空间利用更加集中，个体群居性增加，时空关联率更高，这与被动关联的增加相一致。然而，结果也表明在所有分析的时期都存在主动关联，尽管不同季节的关联有所不同。特别是，雌性似乎会主动避开雄性，这可能是由于个体核心区域收缩导致个体间随机相遇的概率增加所致。我们的框架被证明有助于研究生态和社会限制之间的相互作用，以及这些限制如何影响蜘蛛猴以及可能其他具有高度裂变融合动态的物种的个体活动范围和群体形成决策。
