Cost of multiple matings in female adders (Vipera berus)
Female multiple mating with different partners (polyandry) is taxonomically widespread and appears to be the very prevalent among squamate reptiles (Wusterbarth et al. 2010, and references therein). In this group of animals, females who mate multiply do not gain any direct benefits from the males but may benefit from increased offspring viability as has been observed in some squamates such as adders (Vipera berus, Madsen et al. 1992),water pythons (Liasis fuscus, Madsen et al. 2005), and sand lizards (Lacerta agilis, Olsson et al. 1994). In a recent publication such fitness benefits were again demonstrated in the latter taxon (Olsson et al. 2011). However, in spite of this, the authors stated that “the widespread within-clutch multiple paternity in reptiles are unlikely to be explained by these effects.Amore parsimonious explanation to multiple paternity would be relatively low costs to females for mating multiply and high gains for males.” Although I am one of the authors of this publication, I do not agree with this explanation.