Javascript is not activated in your browser. This website needs javascript activated to work properly.
You are here

Sex ratio variation among broods of great reed warblers Acrocephalus arundinaceus

  • Helena Westerdahl
  • Staffan Bensch
  • Bengt Hansson
  • Dennis Hasselquist
  • Torbjörn von Schantz
Publishing year: 1997
Language: English
Pages: 543-548
Publication/Series: Molecular Ecology
Volume: 6
Issue: 6
Document type: Journal article
Publisher: Wiley-Blackwell

Abstract english

The sex of 746 great reed warbler fledglings (from 175 broods) was determined by the use of single primer polymerase-chain reaction. The reliability of the technique was confirmed as 104 of the fledglings were subsequently recorded as adults of known sex. The overall sex ratio did not differ from unity. Variation in sex ratios between broods was larger than expected from a binomial distribution. Female identity explained some of the variation of brood sex ratio indicating that certain females consistently produced sex ratios that departed from the average value in the population. The theory of sex allocation predicts that parents should adjust the sex ratio of their brood to the relative value of sons and daughters and this may vary in relation to the quality of the parents or to the time of breeding. In the great reed warbler, the proportion of sons was not related to time of breeding, or to any of five female variables. Of five male variables, males with early arrival date tended to produce more daughters. The sex ratio of fledglings that were a result of extra-pair fertilizations did not differ from that of legitimate fledglings. Hence, there is currently no evidence of that female great reed warblers invest in a higher proportion of sons when mated with attractive males.


  • Biological Sciences
  • cuckoldry
  • selection
  • frequency
  • manipulation
  • attractiveness
  • birds
  • genetic-markers
  • RAPD
  • size
  • song repertoire
  • sex ratios
  • sexual selection
  • polygyny
  • laying date


  • Long-term study of great reed warblers
  • Molecular Ecology and Evolution Lab
  • ISSN: 0962-1083
Dennis Hasselquist
E-mail: dennis [dot] hasselquist [at] biol [dot] lu [dot] se



+46 46 222 37 08



Research group


Doctoral students and postdocs

Research fellows


PhD Students, main supervisor

PhD Students, assistant supervisor


Interview about my research in the Swedish podcast "Forskarn & jag"