BORIS Theses

BORIS Theses
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Developmental Influences on Social Competence and Neuroplasticity: The Impact of Early Social Complexity in a Cooperatively Breeding Fish

La Loggia, Océane (2023). Developmental Influences on Social Competence and Neuroplasticity: The Impact of Early Social Complexity in a Cooperatively Breeding Fish. (Thesis). Universität Bern, Bern

23laloggia_o.pdf - Thesis
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Social behaviour plays a pivotal role in shaping the survival, reproduction, and group dynamics of organisms across diverse taxa. Within social groups, individuals must navigate complex social dynamics, communicate effectively, and exhibit appropriate social behaviours to maintain group cohesion and individual fitness. The acquisition of social competence, defined as the ability to adaptively adjust behaviour to the prevailing social context, is therefore crucial for successful social interactions. Evidence consistently points to the early-life social environment as a key determinant of subsequent social behaviour and competence. The work of this thesis aims to provide a comprehensive perspective on the interplay between the early social environment and the acquisition of social competence. I investigated the underlying mechanisms of acquisition of social competence using the cooperatively breeding fish Neolamprologus pulcher as a model species. In chapter one I investigated the impact of group size during early life on expression of social behaviour and other social traits in later life. Social competence was shaped by the early social environment with individuals raised in large groups showing increased flexibility in responding to aggression from a larger conspecific. Large-group fish showed repeatability in social competence contrary to small-group fish, suggesting they reliably show social competence across contexts. On the other hand, helping behaviour, exploration and dispersal were not influenced by the early social environment. With sufficient evidence to support previous findings that group size affects social competence, I set out to find the timing of its acquisition. I showed that early life is the only critical period for acquiring social competence, leaving no chance for recovery in the future. Thirdly, I investigated whether the behavioural patterns observed were linked to specific patterns of neuroplasticity gene expression across the Social Decision-Making Network (SDMN). I measured the expression of three neuroplasticity genes (bdnf and its receptors TrkB and p75NTR) in four regions of the SDMN. I showed that fish raised in large groups display different neuroplasticity gene expression patterns in the SDMN. Taken together my results provide further evidence of the impact of the early social environment on the acquisition of social behaviour. My results suggest that higher social complexity is more likely to yield social phenotypes compatible with group living and thus contribute to maintaining high group size, fuelling sociality in a positive feedback loop.

Item Type: Thesis
Dissertation Type: Cumulative
Date of Defense: 24 November 2023
Subjects: 500 Science > 570 Life sciences; biology
500 Science > 590 Animals (Zoology)
Institute / Center: 08 Faculty of Science > Department of Biology > Institute of Ecology and Evolution (IEE)
Depositing User: Hammer Igor
Date Deposited: 08 Feb 2024 13:33
Last Modified: 08 Feb 2024 13:47

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