Corticosterone mediated mate choice affects female mating reluctance and reproductive success

The study of stress-related hormones as mediators of sexual selection has traditionally focused on the effect of glucocorticoids on male quality and competing ability. However, environmental stressors are expected to affect both males and females, and the strength of sexual selection might be affected by changes in female mating decisions, a hypothesis that has rarely been tested. Here, we investigated whether female common lizard (Zootoca vivipara) mating behaviour and mating preferences are affected by different levels of administered corticosterone and conditioned by the familiarity of their partners, which is known to influence Z. vivipara social behaviour. To this end, two females, one corticosterone-treated and one control female, were simultaneously presented with an unfamiliar male and the following day with either a familiar or an unfamiliar male. Females treated with corticosterone (Cort) were more aggressive towards males and mated less. Furthermore, copulation probability in Cort females, but not in control females, increased with body size. On the second day, Cort females only mated with familiar partners. In contrast, male behaviour towards females was not affected by treatment and only bigger males successfully copulated with Cort females. This shows that corticosterone directly affected female mating behaviour and mating preferences, while male mating behaviour was unaffected by the female's level of corticosterone. Environmental and social stressors may affect reproductive strategies of females, the strength of sexual selection, and sexual conflict through their effects on female glucocorticoid levels, potentially in a wide range of species.