Courtship displays and mounting calls are honest, condition-dependent signals that influence mounting success in Hermann's tortoises

Like other terrestrial tortoises, the courtship behaviour of Hermann's tortoises (Testudo hermanni Gmelin, 1789) is based on a multiple signalling system that involves visual, olfactory, tactile, and acoustic signals. In this study, we analysed relationships between male morphology, hematological profile, courtship intensity, vocalizations, and mounting success in Hermann's tortoises breeding in semi-natural enclosures to investigate the effects of male condition on signals exhibited during courtship and on their mounting success. Results showed that mounting success of Hermann's tortoise males was positively affected by the number of sexual interactions/h, number of bites given to the female during interactions, and by call rate and frequency-modulation range. Call rate, frequency-modulation range, and number of sexual interaction/h increased with hematocrit value, while number of bites given to females decreased with leukocyte concentration. In conclusion, courtship signals exhibited by Hermann's tortoise males, including vocalizations, reliably reveal different components of male condition, and females may use these multiple traits to choose high-quality partners. This is the first study documenting the condition-dependent nature of tortoise courting signals and their effect on male mounting success.