title: Age-dependent trajectories differ between within-pair and extra-pair paternity success.
abstract: Reproductive success is associated with age in many taxa, increasing in early life followed by reproductive senescence. In socially monogamous but genetically polygamous species, this generates the interesting possibility of differential trajectories of within-pair and extra-pair siring success with age in males. We investigate these relationships simultaneously using within-individual analyses with 13 years of data from an insular house sparrow (Passer domesticus) population. As expected, we found that both within- and extra-pair paternity success increased with age, followed by a senescence-like decline. However, the age trajectories of within- and extra-pair paternity successes differed significantly, with the extra-pair paternity success increasing faster, although not significantly, in early life, and showing a delayed decline by 1.5 years on average later in life compared to within-pair paternity success. These different trajectories indicate that the two alternative mating tactics should have age-dependent pay-offs. Males may partition their reproductive effort between within- and extra-pair matings depending on their current age to reap the maximal combined benefit from both strategies. The interplay between these mating strategies and age-specific mortality may explain the variation in rates of extra-pair paternity observed within and between species.
authors.affiliation: Department of Zoology, University of Otago, Dunedin, New Zealand.|Department of Life Science, National Taiwan Normal University, Taipei, Taiwan.
authors.forename: Y-H
authors.identifier: 0000-0002-0233-5045
authors.initials: YH
authors.lastname: Hsu
authors.affiliation: Department of Animal and Plant Sciences, University of Sheffield, Sheffield, UK.
authors.forename: M J P
authors.initials: MJP
authors.lastname: Simons
authors.affiliation: Evolutionary Biology, Max Planck Institute for Ornithology, Seewiesen, Germany.|Department of Life Sciences, Imperial College London, Ascot, Berkshire, UK.
authors.forename: J
authors.initials: J
authors.lastname: Schroeder
authors.affiliation: Evolutionary Biology, Max Planck Institute for Ornithology, Seewiesen, Germany.|Department of Life Sciences, Imperial College London, Ascot, Berkshire, UK.
authors.forename: A
authors.initials: A
authors.lastname: Girndt
authors.affiliation: Department of Animal and Plant Sciences, University of Sheffield, Sheffield, UK.|Evolutionary Biology, Max Planck Institute for Ornithology, Seewiesen, Germany.
authors.forename: I S
authors.identifier: 0000-0001-8606-3720
authors.initials: IS
authors.lastname: Winney
authors.affiliation: Department of Animal and Plant Sciences, University of Sheffield, Sheffield, UK.
authors.forename: T
authors.initials: T
authors.lastname: Burke
authors.affiliation: Department of Zoology, University of Otago, Dunedin, New Zealand.|Department of Animal and Plant Sciences, University of Sheffield, Sheffield, UK.|Evolution & Ecology Research Centre and School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, NSW, Australia.
authors.forename: S
authors.identifier: 0000-0002-7765-5182
authors.initials: S
authors.lastname: Nakagawa
mesh_terms: D000818:Animals; D008297:Male; D010334:Paternity; D012098:Reproduction; D012726:Sexual Behavior, Animal; D046370:Sparrows
keywords: ageing; breeding success; indirect benefits; life-history strategy; mating system; optimal allocation strategy