A defining feature of wild vertebrate populations is the marked variation among individuals in physiology, morphology, life history and behaviour. These differences are shaped by complex interactions between an individual's genetic make-up and the environment it experiences, and are responsible for differences in individual reproductive fitness. Determining the genetic and environmental causes and the fitness consequences of individual variation is therefore fundamental to our understanding of the evolutionary and population dynamics of natural systems.
Fixed differences among individuals in wild animal populations, determined by genes or early-life conditions, are known to be important - but an individual's physiology, behaviour and life history can also change profoundly across its lifetime. Individuals often show improvements in reproductive performance as they gain experience and develop through early life and then show functional deterioration as they reach old age (senescence). Individuals also alter what they do in response to their environment (phenotypic plasticity) and mount physiological defences to challenges from parasites (immunity). While much can be learned about the mechanisms responsible for ageing, plasticity and immunity in laboratory experiments, ultimately the only way to understand how natural selection acts on these processes and how they influence population dynamics is to study them in the wild.
Longitudinal studies, which follow marked and recognisable animals across their lifetimes, reveal that individuals do not just differ in their average size, behaviour or breeding performance. They also differ in the way they develop and senesce, the way they respond to changes in their environment, and the way they respond to and resist parasites. Our research uses long-term individual-based studies of wild animals to understand how genes and environment influence this variation, and what it means for survival, reproduction and ultimately fitness and population size.
Most of our research currently focuses on the remarkable long-term study of Soay sheep on the remote St Kilda archipelago. This represents one of the most detailed studies of a wild mammal anywhere on the planet. Click to go through to the Soay sheep project website to learn more about the animals and the long-term study, or to go to the St Kilda website to learn more about this remarkable place.
Click on the tabs above for more details of specific projects on AGEING, IMMUNITY and TELOMERE DYNAMICS