Nematode parasites reduce carotenoid-based signalling in male red grouse

Jesus Martinez-Padilla, Francois Robert Mougeot, Lorenzo Perez-Rodriguez, Gary R. Bortolotti

Research output: Contribution to journalArticlepeer-review

78 Citations (Scopus)


Carotenoids determine the yellow-red colours of many ornaments, which often function as signals of quality. Carotenoid-based signalling may reliably advertise health and should be particularly sensitive to parasite infections. Nematodes are among the commonest parasites of vertebrates, with well-documented negative effects on their hosts. However, to date, little is known about the effects that these parasites may have on carotenoid-based signalling. Tetraonid birds (grouse) exhibit supra-orbital combs, which are bright integumentary ornaments pigmented by carotenoids. We tested the effect of the nematode parasite Trichostrongylus tenuis on signalling in free-living male red grouse Lagopus lagopus scoticus. We show that experimentally reduced nematode infection increases plasma carotenoid concentration and comb redness, demonstrating for the first time that nematodes can influence carotenoid-based signals.

Original languageEnglish
Pages (from-to)161-164
Number of pages4
JournalBiology Letters
Issue number2
Publication statusPublished - 22 Apr 2007


  • carotenoids
  • comb
  • nematodes
  • red grouse Lagopus lagopus scoticus
  • Trichostrongylus tenuis
  • sexual attractiveness
  • coloration
  • immunocompetence
  • testosterone
  • finches


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