in addition to ingesting carotenoids through the diet, it must suffer a certain level of oxidative stress to show its characteristic red coloration in all its intensity. This coloration would test the strength of the animal, increasing its chances of leaving more offspring. The colored ornaments of many animals are the product of sexual selection as they indicate the quality of the animal. Those individuals with more vivid colors are more likely to be chosen as a couple or avoided by competitors, obtaining more offspring. The yellow, orange and red tones of many vertebrates are produced by certain pigments called carotenoids that, since they cannot be synthesized by the body, are only obtained from the diet. The presence of these shades can thus be a test of your ability to find enough pigment with food.
However, carotenoids are often yellowish Cabo Verde Email List or orange in color and need to be transformed in the animal’s body through enzymatic oxidation reactions to produce more striking pigments, the red ones. “The transformation of these pigments could be physiologically expensive, since a certain level of oxidative stress would be necessary for it to be effective,” contextualizes Carlos Alonso, a researcher at the MNCN. Oxidative stress occurs when there is an imbalance in the body between the levels of antioxidants and free radicals, which causes cell failure related to aging and different diseases. ” For the development of the study, the authors manipulated the levels of different carotenoids in the diet of several specimens of red partridge, a species with red ornaments produced by carotenoids.
In addition, the animals were subjected to a certain oxidative stress by administering a substance that generates free radicals in the water. “As we expected, we verified that the color and the amount of red pigments depended on the abundance of orange carotenoids in the diet (lutein and zeaxanthin), which were transformed. But in addition, we discovered that birds exposed to a certain level of oxidative stress developed redder peaks and deposited a greater amount of the red pigment (astaxanthin) in the ornaments “, clarifies Alonso. In summary, the intense red coloration of the partridge would depend on the composition of the diet and a certain level of oxidative stress. This mechanism could contribute to explain the evolution of red colorations in many species of fish, amphibians, reptiles and birds.