Ethan D. Clotfelter, Daniel R. Ardia, Kevin J. McGraw
Red fish, blue fish: trade-offs between pigmentation and immunity in Betta splendens.
Behavioral Ecology 2007; 18 (6): 1139-1145.
At a very basic level, the fact that dietary supplementation with carotenoids enhances both immunity and coloration (Blount et al. 2003; McGraw and Ardia 2003; Alonso-Alvarez et al. 2004) suggests that carotenoid-limited animals must dedicate carotenoids more to one or another function or suffer both somatically and sexually. Second, experimental manipulations of health status in animals that deposit carotenoids in bare parts (e.g., beaks, legs, and flesh) have shown that immunocompromised animals fade in color (Faivre et al. 2003; Peters et al. 2004), suggesting that carotenoids are retrieved from colorful tissues to fight pathogenic or parasitic challenges.
I’ve been told that fecundity and immunity are two poles of a spectrum, but I didn’t get why.
Use of (limited) dietary carotenoids as either an immunity booster or as a colorant to attract mates are one example!
An amazing article!
Perhaps a partial explanation for why the Hippo Tang (pictured on this blog post) is known to be such a disease prone fish: Not only does one carry the stresses of being a large tang in a fish tank, but apparently the blue color indicates a lack of reserve carotenoids.