Influence of mating preferences on yolk testosterone in the grey partridge

In precocial bird species, the eggs constitute most of the maternal investment because parents do not feed the young after they hatch. Maternal testosterone in egg yolk influences the embryo’s and chick’s development. Females deposit testosterone in the eggs as a response to the environment experienced during the laying period, including the quality of their mate. To assess the relevance of the female’s mate selection on egg characteristics in the grey partridge, Perdix perdix, we tested breeding females in a choice trial where they were allowed to choose between two males. After the choice trials, females were mated either with their preferred male (P group) or with the nonpreferred one (NP group). Although eggs laid by females of the two groups did not differ significantly in mass, females of the P group laid eggs with a higher yolk testosterone concentration than females of the NP group. This study agrees with previous work pointing out that partner attractiveness may play an important role in the transfer of maternally derived egg components.