A UV signal of offspring condition mediates context-dependent parental favouritism

Pierre Bize*, Romain Piault, Benoit Moureau, Philipp Heeb

*Corresponding author for this work

Research output: Contribution to journalArticle

71 Citations (Scopus)

Abstract

As fitness returns during a breeding attempt are context-dependent, parents are predicted to bias their food allocation within a brood from poor towards good condition nestlings when envirorimental conditions deteriorate. We tested this prediction in the Alpine swift and the European starling, two migratory bird species, by modifying an ultraviolet (UV) visual signal of condition in nestlings and exploring how parents allocate food to their young as the season progresses. We show in both species that: (i) UV light reflected by the body skin of offspring positively correlates with their stature (i.e. body mass and skeletal size) and (ii) parental favouritism towards young with more UV reflective skin gradually increases as the season progresses. Early-breeding parents supplied food preferentially to UV pale (i.e. small stature) nestlings, whereas late-breeding parents favoured UV bright offspring (i.e. large stature). These results emphasize that parents use UV signals of offspring condition to adjust their feeding strategies depending on the ecological context.

Original languageEnglish
Pages (from-to)2063-2068
Number of pages6
JournalProceedings of the Royal Society of London. B, Biological Sciences
Volume273
Issue number1597
DOIs
Publication statusPublished - 22 Aug 2006

Keywords

  • parent-offspring interactions
  • honest signalling theory
  • laying date
  • skin reflectance
  • ultraviolet
  • REPRODUCTIVE SUCCESS
  • BIPARENTAL CARE
  • NEED
  • SOLICITATION
  • CONFLICT
  • NESTLINGS
  • DECISIONS
  • QUALITY
  • ABILITY
  • MODELS

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