Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology 288 Age, Longevity and Life-History Trade-Offs in the Collared Flycatcher (Ficedula albicollis) JOANNA SENDECKA ACTA UNIVERSITATIS UPSALIENSIS ISSN 1651-6214 UPPSALA ISBN 978-91-554-6852-1 2007 urn:nbn:se:uu:diva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o! In the orient when the gracious light Lifts up his burning head, each under eye Doth homage to his new-appearing sight, Serving with looks his sacred majesty; And having climbed the steep-up heavenly hill, Resembling strong youth in his middle age, Yet mortal looks adore his beauty still, Attending on his golden pilgrimage: But when from highmost pitch, with weary car, Like feeble age, he reeleth from the day, The eyes, 'fore duteous, now converted are From his low tract, and look another way: So thou, thyself outgoing in thy noon Unlooked on diest unless thou get a son. William Shakespeare The picture on the cover: ‘Åldrandets träd’ was painted by Hillevi Torell. List of papers This thesis is based on the following five papers, which will be referred to in the text by their Roman numerals. I Sendecka, J. & Gustafsson, L. Age-related changes in reproduc- tive performance in Collared flycatchers early in life are shaped by individual quality and optimization of reproductive effort. (Manuscript). II Sendecka, J., CichoĔ, M. & Gustafsson, L. (2007) Age- dependent reproductive costs and the role of breeding skills in the Collared flycatcher. Acta Zoologica 88, 95-100. III Sendecka, J. & Bolund, E. Age-related benefits to female col- lared flycatchers from breeding on high quality territories. (Sub- mited). IV CichoĔ, M., Sendecka, J. & Gustafsson, L. (2003) Age-related decline in humoral immune function in Collared Flycatchers. Journal of Evolutionary Biology 16, 1205-1210. V Sendecka, J. & Gustafsson, L. Longevity and senescence in a wild bird population. (Manuscript). Papers II and IV were reproduced with kind permission of the publisher, The Blackwell Synergy. The order of authors reflects their relative contributions to the papers. I have personally written papers I, II, III and V, performed most of the statistical analyses for papers I, III and V and was deeply involved in the planning of all the experiments and analyses, collection of the field data for all the pa- pers, and lab analyses for paper IV. In all papers coauthors contributed intel- lectually in planning the experiments, final stages of manuscript preparation and data preparation (III). Contents Introduction.....................................................................................................9 Collared flycatchers on Gotland ...................................................................11 Age-dependent survival and reproduction ....................................................13 Why do some individuals live longer than others? ..................................15 What causes age-related changes in reproductive success? .....................16 Early increase in reproductive success ................................................16 Changes in reproductive success late in life ........................................21 Age-related cost of reproduction...................................................................24 Final conclusions and perspectives...............................................................26 Summary in Swedish (Sammanfattning) ......................................................28 Summary in Polish (Streszczenie) ................................................................34 Acknowledgements.......................................................................................39 References.....................................................................................................42 Introduction Longevity and age-related changes in organisms are fascinating topics and active areas of research. This is not only because they apply directly to hu- mans, but also, and maybe even more so, because of the great variation in ageing patterns observed between taxa. For centuries people were consumed by their own ageing without considering the fact that animals also undergo similar ageing processes. Indeed, age-related changes in organisms’ func- tions, including the senescence process are widespread in nature (e.g. Rick- lefs & Scheuerlein, 2001). The basis for many of the major theories on age- ing was provided by August Weismann (1834-1914). He proposed the Germplasm theory which distinguished two different lines within a multicel- lular organism: the germ line and the soma line. This separation provided an explanation for the fact that changes occur within the organism over time without being passed on to the next generation. Thus he provided the starting point for modern theories on ageing. As the field of biology developed, an increasing number of researchers started to address questions about age- related changes in the organism, most of them related either to organismal development or senescence. However, a greater understanding of how organ- isms can change with age and the possible mechanisms responsible for those changes was not possible until the development of modern genetics and evo- lution theories. In 1930 Ronald Aylmer Fisher (1890-1962) provided the basis for life-history theory in his book ‘The Genetical Theory of Natural Selection’. He proposed that organisms face decisions on the distribution of available resources between reproduction and self-maintenance. This as- sumption became a starting point for the theory of senescence, which identi- fies senescence as a result of underinvestment into self-maintenance. How- ever, most of the currently acknowledged hypotheses such as those address- ing age-related changes in reproductive success or senescence process were formulated later, in the second half of the 20th century (Medawar, 1952, Williams, 1957; Hamilton, 1966; Kirkwood, 1977; Charlesworth, 1980). Age-related changes in organismal functions are extremely common. Age-related patterns and signs of senescence in new species are described every day, and almost all the species have now being covered. Even single- celled, asexually reproducing metazoans which were traditionally believed to be immortal show signs of senescence, albeit at a very slow rate (Martinez & Leviton, 1992). Today age differences and ageing receive a lot of interest. The Web of Science displays over a hundred thousand scientific publications 9 containing the term ‘age’ published within only the last five years. Most of these results are related to animals. Why than study age and ageing? With all this research on the topic don’t we already know all there is to know about it? The answer is: absolutely not. Although there are many hypotheses re- garding the underlying causes of age-related patterns, most of these remain to be empirically tested. Studies on ageing in humans and captive mammals are leading the way shifting from external signs of senescence to mecha- nisms acting at the molecular and biochemical level (Arking, 1998). How- ever in field studies, purely age-related changes are often confounded by effects of the environment and interactions with other individuals, effects which are difficult to control for. Moreover, there is huge variation in age- related changes between individuals. Thus, there are large differences in age- related patterns both within and between species and patterns found in labo- ratory studies are not necessarily found in the wild. The aim of this study is explore the patterns of changes in survival prob- ability, reproductive performance, reproductive costs and life-history deci- sions during the initial and final stages of a wild passerine bird’s lifetime. Although an organism’s functions change throughout its lifetime, the most pronounced changes occur at the initial and final stages of lifetime. The pos- sible mechanisms underlying observed changes in survival rates, life-history trade-offs and reproduction will also be tested. 10 Collared flycatchers on Gotland The collared flycatcher (Ficedula albicollis, Temminck, 1795) is a small (~13g), migratory passerine bird belonging to the Old World flycatcher fam- ily (Muscicapidae). Outside the breeding season both sexes possess a cryptic plumage of dull brown, with white patches on the wings