Reproductive Success in Melanistic Adders: A New Hypothesis and Some Considerations on Andrén and Nilson's (1981) Suggestions

After the publication of Andren and Nilson's (1981) study on reproductive success and the risks of predation in normal-coloured and melanistic adders (Vipera berus), interest in the ecological consequences of having a black colour has grown, and other studies have been published. Here, I (1) re-analyse the hypotheses proposed up to now, and (2) suggest a new hypothesis. My conclusions are: (1) black coloration is of selective advantage in female rather than in male adders, (2) one of the possible advantages of being black is that «post-partum» mortality might be lower in melanistic than in cryptic females