We carried out an exhaustive review regarding human skin color variation and how much it may be related to vitamin D metabolism and other photosensitive molecules. We discuss evolutionary contexts that modulate this variability and hypotheses postulated to explain them; for example, a small amount of melanin in the skin facilitates vitamin D production, making it advantageous to have fair skin in an environment with little radiation incidence. In contrast, more melanin protects folate from degradation in an environment with a high incidence of radiation. Some Native American populations have a skin color at odds with what would be expected for the amount of radiation in the environment in which they live, a finding challenging the so‐called “vitamin D–folate hypothesis.” Since food is also a source of vitamin D, dietary habits should also be considered. Here we argue that a gene network approach provides tools to explain this phenomenon since it indicates potential alleles co‐evolving in a compensatory way. We identified alleles of the vitamin D metabolism and pigmentation pathways segregated together, but in different proportions, in agriculturalists and hunter‐gatherers. Finally, we highlight how an evolutionary approach can be useful to understand current topics of medical interest.

This study focuses on a non-social species of butterfly of the Neotropical genus Heliconius, H. erato phyllis, where caterpillar-egg cannibalism may occur. In this species, newly hatched caterpillars are able to recognize sibling eggs, preferentially cannibalizing unrelated when there is a choice. The purpose of this study was to verify whether the information to recognize the egg as sibling or non-kin is in the chorion (maternal origin) and/or in the embryo/young caterpillar, by performing both caterpillar-egg and caterpillar-caterpillar cannibalism tests. The results of these tests suggest that the signal evaluated to recognize kinship is in the egg chorion, not in the caterpillar itself. We discuss these findings in the light of possible nutritional gain and the opportunity of encounters of immatures in a non-social butterfly.