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Individual heterogeneity and senescence in Silvereyes on Heron Island

Knape, Jonas LU ; Jonzén, Niclas LU ; Sköld, Martin; Kikkawa, Jiro and McCallum, Hamish (2011) In Ecology 92(4). p.813-820
Abstract
Individual heterogeneity and correlations between life history traits play a fundamental role in life history evolution and population dynamics. Unobserved individual heterogeneity in survival can be a nuisance for estimation of age effects at the individual level by causing bias due to mortality selection. We jointly analyze survival and breeding output from successful breeding attempts in an island population of Silvereyes (Zosterops lateralis chlorocephalus) by fitting models that incorporate age effects and individual heterogeneity via random effects. The number of offspring produced increased with age of parents in their first years of life but then eventually declined with age. A similar pattern was found for the probability of... (More)
Individual heterogeneity and correlations between life history traits play a fundamental role in life history evolution and population dynamics. Unobserved individual heterogeneity in survival can be a nuisance for estimation of age effects at the individual level by causing bias due to mortality selection. We jointly analyze survival and breeding output from successful breeding attempts in an island population of Silvereyes (Zosterops lateralis chlorocephalus) by fitting models that incorporate age effects and individual heterogeneity via random effects. The number of offspring produced increased with age of parents in their first years of life but then eventually declined with age. A similar pattern was found for the probability of successful breeding. Annual survival declined with age even when individual heterogeneity was not accounted for. The rate of senescence in survival, however, depends on the variance of individual heterogeneity and vice versa; hence, both cannot be simultaneously estimated with precision. Model selection supported individual heterogeneity in breeding performance, but we found no correlation between individual heterogeneity in survival and breeding performance. We argue that individual random effects, unless unambiguously identified, should be treated as statistical nuisance or taken as a starting point in a search for mechanisms rather than given direct biological interpretation. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
breeding, individual heterogeneity, parameter identifiability, senescence, Silvereye, survival, Zosterops lateralis chlorocephalus
in
Ecology
volume
92
issue
4
pages
813 - 820
publisher
Ecological Society of America
external identifiers
  • wos:000290533700003
  • scopus:79955672034
ISSN
0012-9658
DOI
10.1890/10-0183.1
language
English
LU publication?
yes
id
877877cf-ec07-43b8-a57a-d83027966f3e (old id 1986875)
date added to LUP
2011-06-29 10:49:19
date last changed
2017-10-29 03:47:33
@article{877877cf-ec07-43b8-a57a-d83027966f3e,
  abstract     = {Individual heterogeneity and correlations between life history traits play a fundamental role in life history evolution and population dynamics. Unobserved individual heterogeneity in survival can be a nuisance for estimation of age effects at the individual level by causing bias due to mortality selection. We jointly analyze survival and breeding output from successful breeding attempts in an island population of Silvereyes (Zosterops lateralis chlorocephalus) by fitting models that incorporate age effects and individual heterogeneity via random effects. The number of offspring produced increased with age of parents in their first years of life but then eventually declined with age. A similar pattern was found for the probability of successful breeding. Annual survival declined with age even when individual heterogeneity was not accounted for. The rate of senescence in survival, however, depends on the variance of individual heterogeneity and vice versa; hence, both cannot be simultaneously estimated with precision. Model selection supported individual heterogeneity in breeding performance, but we found no correlation between individual heterogeneity in survival and breeding performance. We argue that individual random effects, unless unambiguously identified, should be treated as statistical nuisance or taken as a starting point in a search for mechanisms rather than given direct biological interpretation.},
  author       = {Knape, Jonas and Jonzén, Niclas and Sköld, Martin and Kikkawa, Jiro and McCallum, Hamish},
  issn         = {0012-9658},
  keyword      = {breeding,individual heterogeneity,parameter identifiability,senescence,Silvereye,survival,Zosterops lateralis chlorocephalus},
  language     = {eng},
  number       = {4},
  pages        = {813--820},
  publisher    = {Ecological Society of America},
  series       = {Ecology},
  title        = {Individual heterogeneity and senescence in Silvereyes on Heron Island},
  url          = {http://dx.doi.org/10.1890/10-0183.1},
  volume       = {92},
  year         = {2011},
}