Understanding the causes of individual variation in the rate of ageing is a major topic in gerontology and evolutionary biology with clear application to human health. Nowadays, there is fast growing evidence in a wide range of animal species that, just as in humans, individuals can differ consistently in their behavioural responses to stressors (often encapsulated in the term ‘personality’). However, few studies have addressed the connections between personality and ageing. Different personality types are expected to be associated with different circulating levels of the stress hormone corticosterone, which can in turn hasten telomere erosion and shorten life expectancy. Telomeres are conserved non-coding DNA repeats that protect the end of linear chromosomes and regulate cell replicative potential and thereof organism life expectancy. Furthermore, the importance of genetics versus early and late socio-ecological environments in shaping circulating levels of corticosterone and modulating the links between personality and ageing remains unknown.
To address these questions, this PhD project will build on a 20 year individual-based study in a colonial bird, the Alpine swift. Most offspring are recruited locally, and each year individual propensity to take risk (a personality trait), reproductive success and survival are recorded . Hence, for most individuals detailed information is readily available on their early and late socio-ecological environment, their risk taking behavioural tendencies and their rate of ageing. New and archived samples collected on the same individuals during its life course will be used to decipher cascading effects from propensity to take risk, to stress response (using corticosterone which provides an integrated measure of stress physiology,), telomere erosion and ageing rates. Inter-individual variation in corticosterone levels will be measured in feathers using ELISAs. Telomere length of each individual will be estimated at different ages from blood samples using the latest qPCR approach. State-of-the-art statistical approaches will be applied to study the genetic and phenotypic covariance between risk taking and the rate of ageing, and to test the influence of genetics versus early and late socio-ecological environments on corticosterone, telomere length and ageing rates. Hence, by the end of this project we will know in unprecedented details how and why different personality types are ageing at different rates.
The PhD project will enable the student to learn a variety of important methods in animal physiology and evolutionary biology and to participate in the field work. We will provide a thorough training in laboratory skills, experimental design, basic and advanced statistical analyses, animal eco-physiology and evolutionary biology. The project will be based at the University of Aberdeen and at the University of Edinburgh where the student will benefit from interaction with a thriving community of postgraduate students, postdocs, and faculty in animal physiology and evolutionary biology.
Bize P. et al. 2009. Telomere dynamics rather than age predict life expectancy in the wild. Proceedings of The Royal Society B-Biological Sciences 276: 1679-1683
Bize P. et al. 2012. Experimental evidence that adult antipredator behaviour is heritable and not influenced by behavioural copying in a wild bird. Proceedings of the Royal Society B: Biological Sciences 279: 1380-1388
Bize P. et al. 2017. Negative phenotypic and genetic correlation between natal dispersal propensity and nest-defence behaviour in a wild bird. Biology Letters 1