title: The behavioural, metabolic and proteomic effects of temperature stress on bold and shy beadlet anemones (Actinia equina)
Creators: name: Maskrey, Daniel
Publisher: name: University of Liverpool Repository
Year: 2022

description: Environmental change caused by human activity is an ever-increasing threat to global biodiversity. A key determinant of the survival of animal populations under climate change is intraspecific phenotypic variation. This variation occurs at multiple levels, including between-individual differences in behavioural phenotypes (personalities), varied metabolic rates, and contrasting patterns of proteomic expression. Furthermore, an animal’s behavioural phenotype is split into two levels of its own, such that individuals vary consistently both in their mean level behaviours, and in the residual variation, or unpredictability, that they show around those means. Studies indicate that these different phenotypic levels could often be associated with one another: unpredictability may be constrained, or act as a constraint on, mean level personality; metabolic rate could be positively or negatively correlated with an animal’s propensity to take risks, termed their boldness; and proteomic expression under stress may differ between personality-types. All of these phenotypic levels provide important mechanisms for animals to mitigate against or cope with climate change, but few investigations have yet explored the relationships between them in the context of phenotypic flexibility during environmental shifts, termed plasticity. In this thesis, I explore how acute thermal perturbation, which is predicted to increase in frequency under continued climate change, affects the relationships between behavioural, metabolic, and proteomic phenotypes. Using the beadlet anemone (Actinia equina), a common intertidal species living in a thermally heterogeneous environment, I examine plasticity in two boldness-related behaviours: startle response-time (SRT), defined as the time it takes an anemone to re-extend its tentacles after a threatening stimulus; and immersion response-time (IRT), defined as the time to re-extend tentacles after simulated tidal immersion. In my first and second data chapters, I show that both behaviours exhibit between-individual variation in temperature-driven plasticity at the mean level, and that this extends to the level of unpredictability for IRT. I also show behaviour-dependent associations between temperature-driven behavioural plasticity, genotypic differences, and environmental history. In my third and fourth data chapters, I expand my investigations of each behaviour to encompass temperature-driven plasticity at other phenotypic levels. I find directionally unexpected associations between IRT and metabolic rate, and clear relationships between proteomic expression under thermal stress and SRT. The data presented here provide strong evidence for multi-level associations in temperature-driven phenotypic plasticity, and indicate that several strategies for dealing with thermal perturbation exist in A. equina. They advocate taking account of physiological and molecular correlates when investigating behavioural plasticity in a changing climate, and suggest that some individuals living in intertidal populations are likely to be more at risk from climate change-induced mortality than others. Overall, this thesis reveals the remarkable complexity of intraspecific variation in phenotypic plasticity, and drives home the need for ecologists and conservationists to consider this variation when assessing organismal vulnerability to climate change.