Behavioral Ecology and Sociobiology

, Volume 47, Issue 3, pp 156–163 | Cite as

The effects of testosterone on antibody production and plumage coloration in male house sparrows (Passer domesticus)

  • M. R. Evans
  • A. R. Goldsmith
  • S. R. A. Norris
Original Article

Abstract 

Many bird species have patches of colour in their plumage, contrasting with their basic coloration, which are used to display and signal status to conspecifics. These are called ’badges of status’, because they are believed to be low-cost signals of social status. For a signalling system to be evolutionarily stable, cheating must be controlled. The conventional view is that there is frequent testing, which uncovers cheats. Recently, the immunocompetence handicap hypothesis (ICHH) suggested that signals may be dependent on testosterone for their development, with a cost being imposed through immune suppression. We report experiments on house sparrows (Passer domesticus) which show that testosterone significantly influences the size of the bib (a ’badge of status’). The ultimate effect of the testosterone manipulation was to impair antibody production, as predicted by the ICHH. However, testosterone manipulations also changed the levels of the ’stress hormone’ corticosterone. The level of corticosterone was also related to the degree of immunosuppression. After controlling for the effect of corticosterone, testosterone enhanced the birds’ ability to produce antibodies, counter to the ICHH. The hypothesis therefore must be modified. We suggest that testosterone has a dual effect: it leads to immunosuppression through a mechanism involving corticosterone but, conversely, leads to increased immunocompetence probably via dominance influencing access to resources.

Key words House sparrows Immunity Testosterone Corticosterone Status signalling Immunocompetence handicap hypothesis 

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Copyright information

© Springer-Verlag Berlin Heidelberg 2000

Authors and Affiliations

  • M. R. Evans
    • 1
  • A. R. Goldsmith
    • 2
  • S. R. A. Norris
    • 3
  1. 1.Department of Biological and Molecular Sciences University of Stirling, Stirling, FK9 4LA, UK e-mail: mre2@stir.ac.uk Tel.: +44-1786-467761, Fax: +44-1786 464994GB
  2. 2.School of Biological Sciences, University of Bristol Bristol, BS8 1UG, UKGB
  3. 3.Edward Grey Institute of Field Ornithology, University of Oxford Oxford, OX1 3PS, UKGB

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