Carotenoids and throat pouch coloration in the great frigatebird (Fregata minor)

Frans A. Juola, Kevin McGraw, Donald C. Dearborn

Research output: Contribution to journalArticlepeer-review

21 Scopus citations


Carotenoid pigments are a common source of red, orange, and yellow coloration in vertebrates. Animals cannot manufacture carotenoids and therefore must obtain them in their diet to produce carotenoid-based coloration. Male great frigatebirds (Fregata minor) display a bright red inflated gular pouch as part of their elaborate courtship display. The basis of this coloration until now has not been investigated. Using high-performance liquid chromatography (HPLC), we investigated the types and concentrations of carotenoids that great frigatebirds circulate in their plasma and whether male gular pouch coloration was carotenoid-based. Great frigatebird plasma collected during the breeding season contained three carotenoid pigments in dilute concentrations-tunaxanthin, zeaxanthin, and astaxanthin-with astaxanthin accounting for nearly 85% of the carotenoids present. Astaxanthin was the only carotenoid present in gular pouch tissue, but the concentration is the highest reported for any carotenoid-pigmented avian tissue. Throat pouch reflectance curves were measured with a UV-VIS spectrophotometer, revealing a complex pattern of one UV peak (approx. 360 nm), two absorption valleys (approx. 542 and 577 nm), followed by a plateau at approx 630 nm. The reflectance curve suggests a role for additional pigments, in particular hemoglobin, in the production of color in this ornament.

Original languageEnglish (US)
Pages (from-to)370-377
Number of pages8
JournalComparative Biochemistry and Physiology - B Biochemistry and Molecular Biology
Issue number2
StatePublished - Feb 2008


  • Astaxanthin
  • Carotenoid pigments
  • Color signals
  • HPLC
  • Sexual selection

ASJC Scopus subject areas

  • Biochemistry
  • Physiology
  • Aquatic Science
  • Animal Science and Zoology
  • Molecular Biology


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