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Reproductive Senescence in a Long-Lived Seabird: Rates of Decline in Late-Life Performance Are Associated with Varying Costs of Early Reproduction

For Senegal, whose SWAp provided a promising locus for donor coordination in health in 2005 (see Box 1), the situation is increasingly complex: having been a priority in every development plan to date, SRH as an integrated concept does not appear in either the current Document de Politique Économique et Sociale 2011–2015 (Economic and Social Policy Document 2011–2015; Senegal’s third poverty-reduction strategy paper) or the Plan National de Développement Sanitaire 2009–2018 (National Health Development Plan 2009–2018). Health as a whole appears to have lost its prominence in the current Politique Nationale d’Aide Extérieure au Sénégal (National Policy for External Aid. | vol. 171 no. 2 the AMERICAN naturalist FEBRUARY 2008 E-Article Reproductive Senescence in a Long-Lived Seabird Rates of Decline in Late-Life Performance Are Associated with Varying Costs of Early Reproduction Thomas E. Reed 1 2 Loeske E. B. Kruuk 1 Sarah Wanless 2 Morten Frederiksen 2 3 Emma J. A. Cunningham 1 11 and Michael P. Harris2 1. Institute of Evolutionary Biology King s Buildings University of Edinburgh Edinburgh EH9 3JT United Kingdom 2. Centre for Ecology and Hydrology Bush Estate Penicuik Midlothian EH26 0QB United Kingdom 3. National Environmental Research Institute Department of Arctic Environment University of Aarhus Frederiksborgvej 399 DK-4000 Roskilde Denmark Submitted February 5 2007 Accepted September 18 2007 Electronically published January 3 2008 abstract Evolutionary theories of senescence predict that rates of decline in performance parameters should be shaped by early-life trade-offs between reproduction and somatic maintenance. Here we investigate factors influencing the rate of reproductive senescence in a long-lived seabird the common guillemot Uria aalge using data collected over a 23-year period. In the last 3 years of life individual guillemots had significantly reduced breeding success and were less likely to hold a site or attempt to breed. Females senesced at a significantly faster rate than males. At the individual level high levels of reproductive output earlier in life were associated with increased senescence later in life. This trade-off between early- and late-life reproduction was evident independent of the fact that as birds age they breed later in the season. The rate of senescence was additionally dependent on environmental conditions experienced earlier in life with evidence that harsh conditions amplified later declines in breeding success. Overall individuals with intermediate levels of early-life productivity lived longer. These results provide support for the an-tagonistic-pleiotropy and disposable-soma theories of .