Proximity association in polygynous western black crested gibbons ( Nomascus concolor jingdongensis ): network structure and seasonality

Abstract

Abstract:We investigated the structure and seasonality of the proximity network in a group of polygynous western black crested gibbons (Nomascus concolor) using social network analysis. The spatial proximity changed seasonally and was affected by temperature and rainfall. Preferred proximity association was not distributed randomly among individuals. Kinship was one explanation for the social structure, as offspring preferred to maintain close proximity with their mothers. The proximity of infants to mothers decreased with age, and independent offspring had lower proximity to mothers than dependent ones. We found that the adult male had different proximity relationships with two different adult females. The frequency of proximity between the male and the infant-carrying female was significantly higher than that between the male and the female who had immigrated carrying one offspring of uncertain paternity into the group. Infanticide avoidance and/or predation protection for dependent infants might explain the proximity relationship differences. Temperature influenced group proximity association, with individual proximity increasing in the cold months and decreasing in the hot months. Group proximity decreased in months with higher anthropogenic disturbance.Keywords: Proximity; Nomascus concolor; Polygynous; Social network Spatial distance between individuals exists in all group living animals; however, variances occur among different species and among individuals within the same group. It is reported that spatial distance among individuals is correlated with social relationships (Sade, 1965(Sade, , 1972 and social organization (Kummer, 1968); therefore spatial proximity between group members is important for studying social structure. Early research reported on a correlation between inter-individual distance and social relationship in Macaca mulatta (Sade, 1965), with further studies using spatial data to represent social structure in different primates (e.g. Symphalangus syndactylus: Chivers, 1971; Papio cynocephalus and Saimiri sciureus: Fairbanks, 1976). In recent years, spatial distance has also been used in species with different social structures, such as multi-male-multifemale groups (e.g. Social structure in animal groups can be affected by many factors, such as kinship (Furuichi, 1984;Matsumura & Okamoto, 1997;Silk, 2002), age classes (de Waal & Luttrell, 1986), resource holding potential (Barrett & Henzi, 2006), and resource availability (Henzi et al, 2009). A number of studies have also investigated the relationship between ecological factors and social behavior (Emlen & Oring, 1977;Terborgh, 1986;Sterck et al, 1997;Kappeler & Van Schaik, 2002) and shown that social relationships may change in different seasons (Shimooka, 2003) and habitats (Pruetz & Isbell, 2000). However, compared to numerous studies on the effects of seasonal ecological factors on animal behavior (Dunbar, , 1997), and the development of appropriate measures for spatial proximity can express qualitative variation and assess the...

Adult male–female social bond advertising: The primary function of coordinated singing intensity in a small ape

“…We calculated proportion of proximity, grooming, and behavioral synchronization to quantify adult male-female social bond strength based on behavioral data collected using the 5-min scan method (Fan et al, 2013;Geissmann & Orgeldinger, 2000;Guan et al, 2013a;Guan, et al, 2013b). We defined proximity if the distance between the male and a female was less than 5 m. In this study, behavioral synchronization indicated that individuals engaged in same behavior.…”

Nearest-neighbour clusters as a novel technique for assessing group associations

“…Although the technique described is motivated for raw data consisting of the identities of the spatially nearest individual to all group members, it is possible to use the technique with other forms of data. Where the physical positions in space of individuals in a group have been recorded using biotelemetry techniques [such as [17][18][19][20], it is straightforward to reconstruct nearest-neighbour relationships for all individuals recorded (as figure 1 demonstrates), although it should be acknowledged that data with accurate physical positions of all individuals may yield very different relationship metrics if absolute distances between all individuals are used (so in figure 1, individual C is in the same cluster as F eight times, and in the same cluster as A five times, but is physically closer to A more times than it is to F), suggesting that researchers should be careful in deciding which summary statistic is likely to give the most meaningful interpretation of their data if exact physical distances can be obtained. Temporal proximity could also be used: if animals have to pass through a specific space like a known bottleneck or open space, their passage order can be recorded sequentially (such as in the movement of black-andwhite snub-nosed monkeys, Rhinopithecus bieti, across forest gullies recorded in Neisen et al [20]), with the order of passage through the space being used to construct the association metric.…”