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Health consequences of group living in wild Verreaux’s sifakas (Propithecus verreauxi)

dc.contributor.advisorFichtel, Claudia Dr.
dc.contributor.authorRudolph, Katja
dc.titleHealth consequences of group living in wild Verreaux’s sifakas (Propithecus verreauxi)de
dc.contributor.refereeOstner, Julia Prof. Dr.
dc.description.abstractengThe evolution of sociality exposed individuals to several new health-related costs and benefits, which fundamentally affect their survival and reproductive success. Group living provides better access to food and mates and reduces risks of predation, while it also increases competition over shared resources and facilitates the transmission of pathogens. Whereas the general factors favouring the evolution of group living have been well established, little is known about the underlying mechanisms that link aspects of sociality with health. One reason for this limited understanding is the low number of longitudinal studies that have systematically examined this relationship in wild populations. Here, I add needed data to this field of research by studying links among sociality and indicators of health in 42 individuals of seven neighbouring groups of a wild lemur population - Verreaux’s sifakas (Propithecus verreauxi). These diurnal primates live in multi-male multi-female groups, have a mainly folivorous diet and inhabit the dry forests of southern and south-western Madagascar, where they are exposed to pronounced seasonality. I examined various aspects of Verreaux’s sifakas’ social life, i.e. group size, group membership, rank, affiliative and agonistic interactions, and their potential associations with activity and ranging patterns, parasite infections, measures of faecal glucocorticoid metabolites (fGCMs) and gut microbial communities collected over a study period of two consecutive years. No individual showed signs of sickness and I found only few implications for health-related consequences of sociality in this species. More precisely, group size and social interactions had no impact on behavioural or physiological health-parameters. Between-group variation in activity and ranging patterns likely reflected adaptations to differences in microhabitat features and could be compensated without inflicting changes in fGCMs or parasite infections, i.e. health-related costs. Proximity to group members facilitated the transmission of microorganisms, indicating that gregariousness in this species may indeed come with the cost of parasite transmission, whereas the exchange of beneficial gut microbiota might improve individual health. The results of my thesis imply that health-related consequences of different aspects of group living in Verreaux’s sifakas are limited to the effects caused by social proximity but not social interactions. In conclusion, the magnitude of health consequences of sociality depends on species-specific aspects of their social systems. For example, highly competitive societies with higher rates of agonistic and affiliative interactions among individuals may increase variation in energetic and social stress and facilitate opportunities for transmission of microorganisms. On the contrary, in species with less competitive regimes and low interaction rates, like Verreaux’s sifakas, health-consequences of sociality might be attenuated. More comprehensive wildlife studies conducted on species with different social systems and within an ecologically meaningful context are required to improve our understanding of the complex and interrelated factors that contribute to the sociality-health
dc.contributor.coRefereeDaniel, Rolf Prof. Dr.
dc.contributor.thirdRefereeKappeler, Peter M. Prof. Dr.
dc.contributor.thirdRefereePenke, Lars Prof. Dr.
dc.contributor.thirdRefereeZinner, Dietmar Dr.
dc.subject.engGroup sizede
dc.subject.engGut microbiomede
dc.subject.engPropithecus verreauxide
dc.subject.engHabitat qualityde
dc.affiliation.instituteBiologische Fakultät für Biologie und Psychologiede
dc.subject.gokfullBiologie (PPN619462639)de

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