title: Good reindeer mothers live longer and become better in raising offspring.
abstract: Longevity is the main factor influencing individual fitness of long-lived, iteroparous species. Theories of life history evolution suggest this is because increased longevity allows individuals to (i) have more breeding attempts (time component), (ii) accumulate experience so as to become better able to rear offspring (experience component) or (iii) because individuals reaching old age have above-average quality (quality component). We assess empirically the relative influences of time, experience and quality on the relationship between longevity and individual fitness among female reindeer. Fitness increased with longevity due to all three processes. All females increased in success with age up to their penultimate year of life (experience component), the success of the terminal-breeding occasion was strongly dependent on longevity. Long-lived females had more successful breeding attempts during their life (time component), and had higher reproductive success at all ages, especially during the last year of life (individual quality component) than short-lived females. Our study reveals a more complex relationship between longevity and fitness in large mammals than the simple increase of the number of reproductive attempts when living longer.
authors.affiliation: Department of Animal and Aquacultural Sciences, Norwegian University of Life Sciences, PO Box 5003, 1432 As, Norway.
authors.forename: Robert B
authors.initials: RB
authors.lastname: Weladji
authors.forename: Jean-Michel
authors.initials: JM
authors.lastname: Gaillard
authors.forename: Nigel G
authors.initials: NG
authors.lastname: Yoccoz
authors.forename: Oystein
authors.initials: O
authors.lastname: Holand
authors.forename: Atle
authors.initials: A
authors.lastname: Mysterud
authors.forename: Anne
authors.initials: A
authors.lastname: Loison
authors.forename: Mauri
authors.initials: M
authors.lastname: Nieminen
authors.forename: Nils Chr
authors.initials: NC
authors.lastname: Stenseth
mesh_terms: D000367:Age Factors; D000818:Animals; D005260:Female; D008136:Longevity; D008425:Maternal Behavior; D012053:Reindeer / Q000254:growth & development / Q000502:physiology*; D012098:Reproduction