Testosterone, cuckoldry risk and extra-pair opportunities in the Seychelles warbler

Research output: Contribution to journalArticle


In male birds, testosterone (T) plays an important role in aggressive and mate-attraction behaviour. In the cooperatively breeding Seychelles warbler, Acrocephalus sechellensis, extra-group copulations (EGCs) occur frequently, but are not accompanied by sexual courtship displays as in within-pair copulations. Paternity is nearly always gained by primary males. We investigated whether T levels and sperm storage capability (cloacal protuberance (CP)) in adult primary and subordinate males were related to timing of egg laying, levels of cuckoldry and extra-group paternity (EGP) opportunities. During the sexually active period before egg laying, T levels and CP were only elevated or enlarged (respectively) in primary males, and some suggestion was found that subordinate males do not invest in elevated T levels. The peak in T occurred during the fertile period of the female partner and corresponded to the peak period of male sexual displays and mate guarding, but was independent of cuckoldry risk (density of neighbouring primary males). CP was also enhanced during this period; however, CP but not T remained elevated after egg laying by their mates, and CP but not T was positively related to EGP opportunities (density of neighbouring fertile females). We conclude that T is involved in sexual courtship displays and mate guarding, but not in gaining EGCs. These findings contrast with those in other species where EGP involves elaborate sexual displays.


  • J van de Crommenacker
  • David Richardson
  • TGG Groothuis
  • CM Eising
  • AL Dekker
  • J Komdeur
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Ecology


  • sperm storage, testosterone, Seychelles warbler, paternity, status, cooperative breeding
Original languageEnglish
Pages (from-to)1023-1031
JournalRoyal Society of London. Proceedings B. Biological Sciences
Issue number1543
Publication statusPublished - 2004
Publication categoryResearch

Bibliographic note

The information about affiliations in this record was updated in December 2015. The record was previously connected to the following departments: Animal Ecology (Closed 2011) (011012001)