Antioxidants, showy males and sperm quality

The fertility of males sometimes correlates with their ornamental display, but we do not have a mechanistic explanation to universally link these trai ts. We suggest that both sperm quality (fertility; integrity of DNA), and t he substrates responsible for male ornamentation, may be vulnerable to free radical attack, which can be mitigated by antioxidants. Support for these ideas is at present weak, and requires validation in ecological contexts. W e hypothesize that a link between ornamentation and sperm quality could ari se if antioxidants are in limited supply, and the showiest males may be pre ferred because they are most likely to be fertile, or to provide sperm with undamaged genotypes that could give rise to fit offspring.