Brown spider monkeys ( Ateles hybridus ): a model for differentiating the role of social networks and physical contact on parasite transmission dynamics

Abstract

Elevated risk of disease transmission is considered a major cost of sociality, although empirical evidence supporting this idea remains scant. Variation in spatial cohesion and the occurrence of social interactions may have profound implications for patterns of interindividual parasite transmission. We used a social network approach to shed light on the importance of different aspects of group-living (i.e. within-group associations versus physical contact) on patterns of parasitism in a neotropical primate, the brown spider monkey ( Ateles hybridus ), which exhibits a high degree of fission–fusion subgrouping. We used daily subgroup composition records to create a ‘proximity’ network, and built a separate ‘contact’ network using social interactions involving physical contact. In the proximity network, connectivity between individuals was homogeneous, whereas the contact network highlighted high between-individual variation in the extent to which animals had physical contact with others, which correlated with an individual's age and sex. The gastrointestinal parasite species richness of highly connected individuals was greater than that of less connected individuals in the contact network, but not in the proximity network. Our findings suggest that among brown spider monkeys, physical contact impacts the spread of several common parasites and supports the idea that pathogen transmission is one cost associated with social contact.

Competing pressures on populations: long-term dynamics of food availability, food quality, disease, stress and animal abundance

“…However, the short-term analysis of parasites does not support an effect of group-size on parasitism (C. A. Chapman 2006-2014, unpublished data). Larger groups were associated with fewer parasites, perhaps an effect of behavioural mechanisms such as cliques in social networks that reduce parasite transmission in larger groups [90][91][92][93].…”

Changes in physiological stress and behaviour in semi-free-ranging red-capped mangabeys ( Cercocebus torquatus ) following antiparasitic treatment

“…Parasitic infection may inhibit an individual's ability to engage in energetically costly behaviours, such as challenging dominant individuals [23,24]. Furthermore, social contact and proximity can facilitate parasite transmission [25][26][27], such that animals may modify their behaviour directly to avoid infected conspecifics and reduce infection risk [28].…”

The sociality–health–fitness nexus: synthesis, conclusions and future directions

“…As demonstrated in this issue, it is also crucial to incorporate social structure into studies of the sociality-health-fitness nexus, where social structure describes patterns of contact among individuals in a social group. One paper in this issue details, for example, how contact patterns can be critically important for understanding parasitism in primates [4], while another paper uses comparative analyses and meta-analyses to investigate a positive association between group size and subdivision of those groups [3]. The main point is that group size on its own is often insufficient to explain parasitism in all species; social contact within groups can provide significant traction on these important epidemiological questions, as suggested by previous researchers in the context of measuring network structure [24,25].…”

“…Many of these links have epidemiological implications, resulting in increased spread of infectious diseases through social contact patterns [1][2][3][4] and effects of infectious disease on host behaviour [2]. Other links involve effects of sociality on buffering the stressors of social life, including the intense competition that is observed in some species [5], with resulting effects on susceptibility to infectious and non-infectious diseases when these support networks are unavailable.…”

“…Other papers in this issue have investigated the fitness consequences of sociality and parasitism, for example in Columbian ground squirrels [8]. The papers also take a wide range of approaches, including broad-scale comparative and meta-analysis [3,7,9], long-term field research on food availability, stress and population density [10], social networks and disease spread in wild animals [4], and experimental studies of behaviour in captive primates [5].…”