Male reproductive senescence: the price of immune-induced oxidative damage on sexual attractiveness in the blue-footed booby

Authors


Alberto Velando, Departamento de Ecoloxía e Bioloxía Animal, Campus Lagoas-Marcosende, Universidade de Vigo, 36310 Vigo, Spain. Tel: +34 986812590; Fax: +34 986812556; E-mail avelando@uvigo.es

Summary

  • 1In animals, male reproduction is commonly a function of sexual attractiveness, based on the expression of sexually dimorphic traits that advertise genuinely the male's quality. Male performance may decline with age because physiological functions underlying sexual attractiveness may be affected by senescence.
  • 2Here we show that a sexual signal (foot colour) declines with age, due probably to the deleterious effects of oxidative damage.
  • 3We found that in the blue-footed booby Sula nebouxii foot colour during courtship was less attractive in senescent than in middle-aged males.
  • 4In addition, we increased reactive oxygen species experimentally by immunizing males with lipopolysaccharide, a bacterial cell wall component that induces marked oxidative stress in animals. The immune system activation induced greater lipid peroxidation and invoked changes on colour expression (less attractive), particularly in senescent males.
  • 5These results support the idea that oxidative stress affects reproductive senescence, and suggest that oxidative damage might be a proximal mechanism underlying age-reproductive patterns in long-lived animals.

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