A thesis submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg in fulfilment of the requirements for the degree of Doctor of Philosophy
2017 / Social systems describe the social organisation, mating system and social interactions of a species, and are revealing of the nature of how animals live and the underlying mechanisms of living alone or in groups. The social system of the African woodland dormice Graphiurus murinus has not been documented. The aim of my study was to investigate sociality, the mechanisms promoting sociality, and to G. murinus along the continuum of sociality in respect of rodents. Investigations on nest sharing in free-living woodland dormice showed that sleeping associations were common in females than males but changed seasonally (females all year round; males in breeding and winter seasons), reflecting the reproductive and thermoregulatory needs. The social structure of these sleeping associations was assessed using association indices and social network analysis. Woodland dormice exhibited a web of relationships between sex and age groups, with adult female groups and juvenile groups forming strong and exclusive relationships, while male groups showed ephemeral and weak relationships. In staged dyadic encounters of same sex dyads in captivity, females were amicable and tolerated unfamiliar females, whereas males displayed low tolerance and aggression towards unfamiliar. The three-chamber paradigm tests for sociability and social preferences revealed that both adult males and females had an intrinsic motivation to be social. However, this motivation differed by sex, with females showing a greater affinity for both strangers and unfamiliar females, whereas males showed an affinity for familiar males. Observations of huddling in female dyads revealed that, under decreasing Ta, females huddled together and combined nest material, thus changing the local microclimate and the insulation capacities of nests. In addition, long-associations were maintained even after Ta was increased, revealing that thermal challenges might promote group formation and enhance familiarity amongst females. Both my field and laboratory data suggest that woodland dormice form small seasonally transient sleeping associations. In females, limited aggression, tolerance, and nest sharing and construction under low temperatures could also lead to prolonged group-living. In males, aggression towards unfamiliar males, possibly maintains intra-sexual territoriality, yet familiarity creates tolerance, leading to group-living. Group-living in this arboreal rodent is mediated by the apparently phylogenetically constrained energetic demands of thermoregulation, coupled with an inherent need to associate with conspecifics. The level of familiarity between conspecifics or the presence of social partners facilitates group formation and is shaped by prevailing ecological conditions. / MT 2017
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:wits/oai:wiredspace.wits.ac.za:10539/23507 |
| Date | January 2017 |
| Creators | Madikiza, Zimkitha Josephine |
| Source Sets | South African National ETD Portal |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Format | Online resource (xiii, 160 leaves), application/pdf |
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