Carotenoids, Immunocompetence, and the Information Content of Sexual Colors: An Experimental Test

  title={Carotenoids, Immunocompetence, and the Information Content of Sexual Colors: An Experimental Test},
  author={Kevin J. McGraw and Daniel R. Ardia},
  journal={The American Naturalist},
  pages={704 - 712}
Many male birds use carotenoid pigments to acquire brilliant colors that advertise their health and condition to prospective mates. The direct means by which the most colorful males achieve superior health has been debated, however. One hypothesis, based on studies of carotenoids as antioxidants in humans and other animals, is that carotenoids directly boost the immune system of colorful birds. We studied the relationship between carotenoid pigments, immune function, and sexual coloration in… 

Effect of Dietary Carotenoid Supplementation on Food Intake and Immune Function in a Songbird with no Carotenoid Coloration

Finnish affinities for carotenoid-rich foods may be particular to species with sexually selected carotENoid pigmentation, but that, as in humans and other mammals, the immune-boosting action ofcarotenoids is conserved regardless of the strength of sexual selection on pigment use.

Carotenoids, immune response and the expression of sexual ornaments in male greenfinches (Carduelis chloris)

The idea that carotenoids are a limiting resource and that males trade ornamental colouration against immune response supports the idea thatCarotenoid availability in the diet was related to variation in antibody response to novel antigens in male greenfinches.

Immunoregulatory activity of different dietary carotenoids in male zebra finches

This study experimentally tested how two common dietary xanthophylls - lutein and zeaxanthin - may differentially affect the immune system in male zebra finches (Taeniopygia guttata).

Do carotenoids buffer testosterone-induced immunosuppression? An experimental test in a colourful songbird

These findings highlight a nutrient-specific mechanism by which animals escape high immune costs of T elevation and thus can still elevate ornamentation in animals like birds and fishes.

Carotenoids increase immunity and sex specifically affect color and redox homeostasis in a monochromatic seabird

The results indicate that the trade-off responses to carotenoid availability are sex-specific in kittiwakes and yellow xanthophylls enhance the innate immune system in k Kittiwakes.

Differential Accumulation and Pigmenting Ability of Dietary Carotenoids in Colorful Finches

Zeaxanthin is preferentially accumulated in the body and serves as a more potent substrate for pigmentation than lutein in these finches, demonstrating that zeaxanthine plays unique roles in shaping the ultimate color expression of individuals.

Carotenoid‐Based Plumage Colors and Immune Function: Is There a Trade‐Off for Rare Carotenoids?

The results indicate that honesty of carotenoid‐based signals is maintained by an individual’s physiological limitation to absorb and/or transportCarotenoids and by access to carotanoids, indicating that preferences for carOTenoids‐based traits in sexual selection or parent‐offspring interactions select for competitive individuals, rather than specifically for immune function.

Carotenoid deprivation and beta-carotene's effects on male and female turtle color.

Availability of non-carotenoid antioxidants affects the expression of a carotenoid-based sexual ornament

The data suggest that carotenoid-based ornaments may honestly signal an individual's availability of non-carotenoids antioxidants, allowing females to make adaptive mate-choice decisions.

Carotenoids bolster immunity during moult in a wild songbird with sexually selected plumage coloration

This study provides experimental, seasonal support for a fundamental tenet of Lozano's ‘carotenoids trade-off’ hypothesis and adds to a growing list of animal species that benefit immunologically from ingesting higher dietary carotenoid levels.



Dietary carotenoids predict plumage coloration in wild house finches

Testing the gut contents of moulting house finches and comparing the concentration of carotenoid pigments in their gut contents with the colour of growing feathers found a positive association: males that ingested food with a higher concentration ofcarotenoids grew brighter ornamental plumage.


Results suggest that physiological factors such as pigment transport may play a more important role in shaping variability in carotenoid-based bill coloration in this species than does diet.

Carotenoid-based plumage coloration of male greenfinches reflects health and immunocompetence

Results suggest that carotenoid-based plumage coloration in greenfinches honestly signals immunocompetence and health status.

Carotenoid Modulation of Immune Function and Sexual Attractiveness in Zebra Finches

It is shown that manipulation of dietary carotenoid supply invokes parallel changes in cell-mediated immune function and sexual attractiveness in male zebra finches (Taeniopygia guttata).

The effect of a carotenoid-rich diet on immunocompetence and behavioural performances in Moorhen chicks

It is demonstrated that carotenoid abundance can influence both immune and behavioural responses, with a greater availability ofcarotenoids being reflected in improved behavioural performance and immunocompetence.

Carotenoids and egg quality in the lesser black-backed gull Larus fuscus: a supplemental feeding study of maternal effects

The results suggest that carotenoids could be one resource responsible for egg quality maternal effects in birds, and the possible implications of carOTenoid–mediated effects on phenotype for fitness in mothers and their offspring are discussed.

Anhydrolutein in the zebra finch: a new, metabolically derived carotenoid in birds.

Dietary carotenoids and human immune function.

Is There an Immunological Cost to Carotenoid‐Based Ornamental Coloration?

  • G. Hill
  • Biology
    The American Naturalist
  • 1999
It seems likely that parasite load and limited access to dietary carotenoids combine to determine color expression in many species of animals.

Carotenoids, Immunity, and Sexual Selection: Comparing Apples and Oranges?

  • G. Lozano
  • Psychology
    The American Naturalist
  • 2001
Hill (1999) outlined several alleged inconsistencies that “have been ignored or overlooked in the growing literature pro-moting the idea of carotenoids as signals of immuno-competence,” but his arguments and supporting evidence require careful scrutiny.