Abstract
Climate change is leading to increased mean temperatures and more frequent and severe temperature anomalies, threatening organisms globally. Phenotypic plasticity, the ability of a given genotype to express different phenotypes in different environments, may offer a mechanism that allows organisms to temporarily persist in a rapidly changing environment, ultimately buying time for genetically based adaptations to evolve. Plasticity has been demonstrated both within and across generations, in response to different environmental stressors. However, our understanding of the interactive effects of plastic responses across levels of biological organisation, and over temporal scales from hours to generations, is still limited. Additionally, we do not yet have a comprehensive knowledge of how plasticity may interact with other evolutionary processes such as selection. This thesis explores the role of plasticity in enabling estuarine amphipod species to cope with environmental warming within and across generations. I first present a review on the state of the art of plasticity research, with a particular focus on the current challenges within the study of transgenerational plasticity. In chapter two, I explore whether pre-exposure to an acute thermal challenge leads to inducible stress tolerance in Marinogammarus marinus. I demonstrate that this mode of pre-exposure did not induce improved thermal or hypoxia tolerance, and instead led to increased susceptibility to a subsequent thermal challenge occurring 24 h after initial pre-exposure. Chapter three documents the effect of chronic warming on the shape of thermal performance curves across levels of organisation in Gammarus chevreuxi. I demonstrate that chronic warming led to trait-dependent patterns of phenotypic plasticity, evidenced by modulations of the shape of thermal performance curves. Finally, chapter four explores how the effects of chronic warming interact within and across generations to influence the functional performance and fitness of Gammarus chevreuxi. This chapter demonstrates that these estuarine amphipods may be limited in their ability to induce thermal plasticity within a generation and may not be able to rapidly buffer themselves against the detrimental fitness effects of climate warming. Within a generation, chronically warmed G. chevreuxi exhibited some plasticity, particularly in metabolism. However, this was accompanied by clear evidence of reduced transient fecundity and fitness in these warming conditions. Transgenerational warming led to strong selection pressure that, in combination with possible transgenerational plasticity, could alter the average population response to warming over generations. Both parental and offspring warming improved the sublethal thermal performance of offspring when applied independently. However, the effects of both environments interacted, such that when parents and offspring were both warmed, this beneficial plasticity was negated; a potentially maladaptive consequence of cumulative stress of warming that persists across generations. Future work should consider the interaction of plasticity within and across generations, as well as its relationship with selection and fitness, to elucidate the evolutionary outcomes of environmental change across generations.
Awarding Institution(s)
University of Plymouth
Award Sponsors
Natural Environment Research Council (NERC) and ARIES Doctoral Training Partnership (DTP), grant ref: NE/S007334/1
Supervisor
Manuela Truebano, Pete Cotton, Enrico Rezende, Melody Clark, Helen Findlay
Keywords
Phenotypic plasticity, Transgenerational plasticity, Ecophysiology, Evolutionary biology, Amphipod, Thermal performance curve, Cross-protection, Heat hardening, Crustacean
Document Type
Thesis
Publication Date
2026
Embargo Period
2026-05-07
Deposit Date
May 2026
Additional Links
Creative Commons License
This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License
Recommended Citation
McAndry, C. (2026) Coping with climate change: the role of plasticity within and across generations. Thesis. University of Plymouth. Available at: https://doi.org/10.24382/6g5x-xv22
