Causes and Consequences of Among-Individual Variation in Behaviour in Animal Populations

  • Author / Creator
    Haave Audet, Elene
  • The field of animal personality, the study of adaptive among-individual behavioural differences in animal populations, has both exploded in popularity in the last few decades and come under heavy scrutiny by behavioural ecologists. The sudden interest in the field stems from the widespread finding that individuals in populations often behave consistently differently from one another, even across contexts, while the criticism stems from the lack of ecological relevance of many studies on the topic and the lack of grounding in testable theoretical predictions. My thesis is centered on 1) testing current theory about the mechanisms maintaining adaptive behavioural variation in populations over generations and 2) evaluating the fitness consequences of behavioural differences in an understudied, yet ecologically relevant, behaviour: sampling. First, I conducted a systematic review and meta-analysis to test the hypothesis that among-individual differences in behaviour are maintained because they reflect differences in the allocation toward survival versus reproduction, effectively a trade-off between survival and reproduction mediated by behaviour. My study was comprised of 760 estimates from 194 studies, and I found that contrary to predictions, the relationship between behaviour and fitness could not be explained by trade-offs between survival and reproduction, pointing to the potential role of individual differences in resource acquisition in mediating the relationship between behavioural expression and fitness outcomes in animal populations. Second, I conducted a field study using a model system, the black-capped chickadee (Poecile atricapillus), to assess whether there are among-individual differences in sampling behaviour (i.e., gathering information about a resource patch to assess its profitability to manage uncertainty about resource availability), and whether such differences predict annual survival in the population. In our sample of 132 individually marked chickadees, we found that chickadees sample under two distinct sets of conditions— when the risk of starvation was high and when the risk of starvation was low—and adjusted their sampling behaviour under these two sets of conditions in response to ambient temperature as predicted by existing models of optimal sampling.
    Interestingly, there was a very strong among-individual covariance between the two types of sampling, and we found moderate support that individuals that invest more in sampling overall also had higher annual survival. The positive covariance between the two types of sampling can only be understood in light of individual differences in access to resources, and I discuss how resource heterogeneity, which I identified as being a key mediator in the relationship between individual behaviour and fitness using meta-analysis, needs to be a central focus in future work addressing adaptive behavioural differences in animal populations.

  • Subjects / Keywords
  • Graduation date
    Fall 2021
  • Type of Item
  • Degree
    Master of Science
  • DOI
  • License
    This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.