Courtship Displays Are Condition-Dependent Signals That Reliably Reflect Male Quality in Greek Tortoises, Testudo graeca

The courtship behavior of male Greek tortoises (Testudo graeca) is based on a multiple signaling system that involves tactile, visual, olfactory, and acoustic signals. In some recent studies on marginated (Testudo marginata) and Hermann's tortoises (Testudo hermanni) we showed that male mounting success was significantly and positively correlated to the intensity of courtship displays. This was due to the number of rams and bites and the number of calls emitted during mounting, which are considered to be condition-dependent signals that reliably convey information on male quality. In this correlative study, we analyzed relationships between male morphology, hematological profile, courtship intensity, vocalizations, and mounting success in a group of 104 Greek tortoises breeding in seminatural enclosures. As expected, our study showed that mounting success of males was positively correlated to the number of rams and the frequency of interactions during courtship and negatively correlated to the call duration. Moreover the hematocrit was positively correlated with the call rate and the number of rams. Therefore, courtship signals exhibited by male Greek tortoises, including vocalizations, reliably reveal different components of male condition, and females may use these signals to choose high-quality partners, as previously observed in marginated and Hermann's tortoises.