Evolutionary ecology of senescence in the wild

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Not long ago, senescence in animals was dismissed as an artifact of the lab as it was widely believed that few wild animals lived long enough to senesce. We now know that senescence is not only detectable in the wild, but up to 90% of mortality in very long-lived animals is associated with senescence. Yet we still have a poor understanding of the processes underlying senescence in the wild, how those processes cause variation in life-history and fitness, and how ageing processes occurring in the lab translate to the wild. Using two model systems both involving flying organisms, Drosophila that have evolved under predation and starvation (one project) and long-lived seabirds at two long-term field stations (three projects), my students and I propose to unravel some of these mysteries. First, we propose to investigate the underlying processes by exploring whether muscle damage leading to reduced foraging abilities is a major cause of senescence in the wild. Second, we propose to test the ecological ramifications of ageing by testing the idea that life-history trajectories depend largely on biological age (physiological condition) rather than chronological age. Third, we propose to examine whether individual plasticity in ageing trajectories is associated with fitness. Lastly, we propose to test evolutionary theory by experimentally selecting for Drosophila with high levels of naturally occurring mortality to determine how variation in extrinsic mortality can influence intrinsic mortality rates. We are interested in how ageing in lab-adapted Drosophila translates to ageing in "wild" (starved and hunted) Drosophila. My research program will provide insight into the evolutionary ecology of senescence in the wild. A comparative approach to such basic research may impact our ability to prolong the healthy lifespan of animals and to provide age-structured models for wildlife conservation. **