From parent to population: the influence of the social environment on individual fitness

Bebbington, Kathryn (2017) From parent to population: the influence of the social environment on individual fitness. Doctoral thesis, University of East Anglia.

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In this thesis, I investigated how the social environment � the phenotypes of all an individual�s social partners � influences metrics related to individual fitness. Using data from a population of cooperatively breeding Seychelles warblers Acrocephalus sechellensis, I explored relationships between various fitness-related parameters (body condition, telomere length, reproductive success and survival) and components of the social environment during both development and adulthood. I first investigated whether the presence of a nestmate influenced nestling physiological costs. While nestmate presence during development was costly, this cost was lower for relatively strong competitors. Intriguingly, strong competitors who survived to adulthood outperformed those raised alone in the nest. I further investigated early-life competition in the context of communal breeding, where two females sometimes raise their offspring in a joint-nest. Relatedness between competitors, which should dictate the degree of conflict over parental resources, had no effect on the cost of competition, most likely because conflict was resolved through increased parental provisioning in communal nests. Next, I examined how mate choice affects reproductive success by testing for offspring inbreeding depression. Individuals who reproduced with a relative produced offspring with shorter telomeres, but this was mainly evident in low-quality years. I also explored the influence of adult social partners on fitness-linked metrics, both within social groups and between neighbouring groups. Within groups, dominants appeared to benefit from larger group sizes, while subordinate females had better condition in small groups. At the population level, I found that male territory owners gained mass and lost telomeres when their male neighbours were either relatives or familiar individuals. The benefit of having related or familiar neighbours was greatest in high-density areas of the population. My research demonstrates the importance of considering ecological context, such as resource availability and intrinsic individual properties, when attempting to understand the link between socially-mediated behaviour and fitness.

Item Type: Thesis (Doctoral)
Faculty \ School: Faculty of Science > School of Biological Sciences
Depositing User: Bruce Beckett
Date Deposited: 26 Jul 2018 11:01
Last Modified: 21 Sep 2020 00:38


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