Behavioral Ecology and Sociobiology

, Volume 39, Issue 5, pp 317–322

Sexual ornamentation, condition, and immune defence in the house sparrow Passer domesticus

Authors

  • A. P. Møller
    • Laboratoire d’Ecologie, CNRS URA 258, Université Pierre et Marie Curie, Ba^t. A, 7ème étage, 7 quai St. Bernard, Case 237, F-75252 Paris Cedex 5, France
  • R. T. Kimball
    • Department of Biology, 167 Castetter Hall, University of New Mexico, Albuquerque, NM 87131-1091, USA
  • J. Erritzøe
    • Taps Old Rectory, DK-6040 Christiansfeld, Denmark

DOI: 10.1007/s002650050295

Cite this article as:
Møller, A., Kimball, R. & Erritzøe, J. Behav Ecol Sociobiol (1996) 39: 317. doi:10.1007/s002650050295

Abstract

Female mate preferences for extreme male ornaments may arise and be maintained because males signal their ability to raise an immune defence against parasites by the size of their ornaments. The bursa of Fabricius is an organ involved in antibody synthesis in young birds, but regresses before sexual maturity. The relationship between badge size, condition, and immune defence was investigated in male house sparrows, Passer domesticus, which have a bib of black feathers under their beak, a secondary sexual character currently subject to a directional female mate preference. The size of the bursa of Fabricius decreased during the first year of life in house sparrows. Males with large secondary sexual characters had a smaller bursa than males with small badges. Individuals with a large directional asymmetry in relative testis size had a larger bursa. The abundance of one parasite (a mallophagan) was positively related to bursa size. There was a positive relationship between relative volume of bursa of Fabricius and the number of fault bars on feathers, which is a measure of body condition. These results suggest that males with large badges have lower current levels of immune response than males with small badges, and that males in good body condition, as evidenced from the absence of fault bars, had a relatively small bursa of Fabricius.

Key words Bursa of FabriciusImmunocompetenceOrnamentsSexual selection

Copyright information

© Springer-Verlag Berlin Heidelberg 1996