Testing evolutionary models of senescence in a natural population

age and inbreeding effects on fitness components in song sparrows

L. F. Keller, J. M. Reid, P. Arcese

Research output: Contribution to journalArticle

70 Citations (Scopus)

Abstract

Mutation accumulation ( MA) and antagonistic pleiotropy ( AP) have each been hypothesized to explain the evolution of `senescence' or deteriorating fitness in old age. These hypotheses make contrasting predictions concerning age dependence in inbreeding depression in traits that show senescence. Inbreeding depression is predicted to increase with age under MA but not under AP, suggesting one empirical means by which the two can be distinguished. We use pedigree and life-history data from free-living song sparrows ( Melospiza melodia) to test for additive and interactive effects of age and individual inbreeding coefficient (f) on fitness components, and thereby assess the evidence for MA. Annual reproductive success (ARS) and survival ( and therefore reproductive value) declined in old age in both sexes, indicating senescence in this short-lived bird. ARS declined with f in both sexes and survival declined with f in males, indicating inbreeding depression in fitness. We observed a significant age! f interaction for male ARS ( reflecting increased inbreeding depression as males aged), but not for female ARS or survival in either sex. These analyses therefore provide mixed support for MA. We discuss the strengths and limitations of such analyses and therefore the value of natural pedigreed populations in testing evolutionary models of senescence.

Original languageEnglish
Pages (from-to)597-604
Number of pages8
JournalProceedings of the Royal Society of London. B, Biological Sciences
Volume275
Issue number1635
Early online date23 Jan 2008
DOIs
Publication statusPublished - 22 Mar 2008

Keywords

  • ageing
  • gene-environment interactions
  • life history
  • longevity
  • mortality
  • melospiza-melodia
  • reproductive-performance
  • genetic variance
  • depression
  • survival
  • wild
  • heterogeneity
  • probabilities
  • immigration

Cite this

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title = "Testing evolutionary models of senescence in a natural population: age and inbreeding effects on fitness components in song sparrows",
abstract = "Mutation accumulation ( MA) and antagonistic pleiotropy ( AP) have each been hypothesized to explain the evolution of `senescence' or deteriorating fitness in old age. These hypotheses make contrasting predictions concerning age dependence in inbreeding depression in traits that show senescence. Inbreeding depression is predicted to increase with age under MA but not under AP, suggesting one empirical means by which the two can be distinguished. We use pedigree and life-history data from free-living song sparrows ( Melospiza melodia) to test for additive and interactive effects of age and individual inbreeding coefficient (f) on fitness components, and thereby assess the evidence for MA. Annual reproductive success (ARS) and survival ( and therefore reproductive value) declined in old age in both sexes, indicating senescence in this short-lived bird. ARS declined with f in both sexes and survival declined with f in males, indicating inbreeding depression in fitness. We observed a significant age! f interaction for male ARS ( reflecting increased inbreeding depression as males aged), but not for female ARS or survival in either sex. These analyses therefore provide mixed support for MA. We discuss the strengths and limitations of such analyses and therefore the value of natural pedigreed populations in testing evolutionary models of senescence.",
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author = "Keller, {L. F.} and Reid, {J. M.} and P. Arcese",
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TY - JOUR

T1 - Testing evolutionary models of senescence in a natural population

T2 - age and inbreeding effects on fitness components in song sparrows

AU - Keller, L. F.

AU - Reid, J. M.

AU - Arcese, P.

PY - 2008/3/22

Y1 - 2008/3/22

N2 - Mutation accumulation ( MA) and antagonistic pleiotropy ( AP) have each been hypothesized to explain the evolution of `senescence' or deteriorating fitness in old age. These hypotheses make contrasting predictions concerning age dependence in inbreeding depression in traits that show senescence. Inbreeding depression is predicted to increase with age under MA but not under AP, suggesting one empirical means by which the two can be distinguished. We use pedigree and life-history data from free-living song sparrows ( Melospiza melodia) to test for additive and interactive effects of age and individual inbreeding coefficient (f) on fitness components, and thereby assess the evidence for MA. Annual reproductive success (ARS) and survival ( and therefore reproductive value) declined in old age in both sexes, indicating senescence in this short-lived bird. ARS declined with f in both sexes and survival declined with f in males, indicating inbreeding depression in fitness. We observed a significant age! f interaction for male ARS ( reflecting increased inbreeding depression as males aged), but not for female ARS or survival in either sex. These analyses therefore provide mixed support for MA. We discuss the strengths and limitations of such analyses and therefore the value of natural pedigreed populations in testing evolutionary models of senescence.

AB - Mutation accumulation ( MA) and antagonistic pleiotropy ( AP) have each been hypothesized to explain the evolution of `senescence' or deteriorating fitness in old age. These hypotheses make contrasting predictions concerning age dependence in inbreeding depression in traits that show senescence. Inbreeding depression is predicted to increase with age under MA but not under AP, suggesting one empirical means by which the two can be distinguished. We use pedigree and life-history data from free-living song sparrows ( Melospiza melodia) to test for additive and interactive effects of age and individual inbreeding coefficient (f) on fitness components, and thereby assess the evidence for MA. Annual reproductive success (ARS) and survival ( and therefore reproductive value) declined in old age in both sexes, indicating senescence in this short-lived bird. ARS declined with f in both sexes and survival declined with f in males, indicating inbreeding depression in fitness. We observed a significant age! f interaction for male ARS ( reflecting increased inbreeding depression as males aged), but not for female ARS or survival in either sex. These analyses therefore provide mixed support for MA. We discuss the strengths and limitations of such analyses and therefore the value of natural pedigreed populations in testing evolutionary models of senescence.

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KW - gene-environment interactions

KW - life history

KW - longevity

KW - mortality

KW - melospiza-melodia

KW - reproductive-performance

KW - genetic variance

KW - depression

KW - survival

KW - wild

KW - heterogeneity

KW - probabilities

KW - immigration

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