Testing the evolutionary theory of senescence in wild vertebrate and historical human populations

My work over the course of this postdoctoral fellowship has substantially advanced our understanding of the causes and consequences of individual variation in ageing in wild animal populations. Since starting the fellowship, I have produced 10 peer-reviewed publications (see publication list section) and have several more manuscripts related directly to the aims in the fellowship proposal currently either in review or in preparation. In the work published since the fellowship began, I have presented some of the most compelling evidence to date in support of evolutionary theories of ageing from wild animal populations. I have been to show that, in wild ungulates:
- As predicted by evolutionary theory, variation in ageing rates in annual fitness traits has an additive genetic basis.
- As predicted by the antagonistic pleiotropy theory of ageing, investment in reproduction in early life results in more rapid ageing rates in later life and that this trade-off has a genetic basis.
- Poor environmental conditions in early life exacerbate ageing rates in survival and reproduction in later adulthood.
- As classical evolutionary theory predicts, males show more rapid reproductive senescence than females but – unexpectedly – different reproductive traits senesce at different rates within each sex.
- As predicted by free radical theories of ageing and life history evolution, faster growth in early life is associated with increased levels of oxidative damage, although oxidative damage does not appear to increase with age.
During the fellowship, I was also invited to co-edit and contribute a review to a special themed issue of the journal Functional Ecology on ‘the evolutionary ecology of senescence’ in 2008. More recently, I was also invited to help produce a unique guide to the application of quantitative genetic analytical techniques for ecologists for Journal of Animal Ecology. I have co-organised a day-long symposium on ageing in wild populations as part of the 2007 European Society for Evolutionary Biology Congress in Uppsala, Sweden. I recently helped set up an organisation that aims to bring together researchers interested studying ageing from across Scottish universities on an annual basis (Scottish Ecological Ageing Research Group), the second annual meeting of which ran successfully in summer 2010.
Some of the work in the original proposal is still ongoing and I expect this will result in publications over the coming year or so. The work proposed on the historical human populations in Quebec has begun to bear fruit after considerable efforts to organise the data set into a manageable database format. Analyses investigating the fitness consequences of inbreeding and the quantitative genetics of fitness in the Isle-aux-Coudres population (collaborators: F Meyer & D Réale) are now complete and two manuscripts are currently in preparation. Ongoing investigations of senescence in body mass and factors influencing actuarial senescence in several wild ungulate populations (collaborators: J Pemberton, L Kruuk, T Clutton-Brock, T Coulson, J-M Gaillard & M Festa-Bianchet) are also currently ongoing, with one manuscript in preparation.
Finally, the support provided by this postdoctoral fellowship has allowed me to establish new collaborations with researchers working on other systems and in different fields and obtain funding to pursue these new research questions. I am co-investigator on recently funded NERC response mode grant to study ageing in a wild mongoose population and have recently been awarded a BBSRC David Phillips fellowship to follow-on from the NERC postdoctoral fellowship to study the links between early-life experiences and ageing in a wild sheep population.