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

Carotenoid-based integument coloration is extremely widespread in animals and commonly used as an honest signal of condition in sexual selection. Besides being used for color expression, carotenoids have antioxidant and immunomodulatory activity. Being a limited resource, carotenoid allocation to competing demands generates a trade-off. Recent studies, however, suggest that the antioxidant role of carotenoids might not be as important as...