Preference for the other sex: Olfactory sex recognition in terrestrial fire salamanders (Salamandra salamandra)

Finding a potential mate, that is an individual of the opposite sex, is a fundamental step for sexual reproduction in animal species. Signals involved in the context of mate attraction are mediated by acoustic, visual, and/or chemical signals. For amphibians in general, and especially for many newt and salamander species, chemical cues are known to play important roles in inter- and intraspecific communication. We therefore investigated the use of olfactory cues for sex recognition in terrestrial fire salamanders (Salamandra salamandra) that belong to the group of true salamanders within the Salamandridae. Specifically, we performed odor preference tests with adult salamanders of both sexes and tested whether substrate-borne chemical cues provide sex-specific signals. We found an overall preference for chemical cues of the opposite sex, i.e. males and females differed significantly in their preference for a specific sex. Females spent significantly more time in the compartment with the chemical cues of a male, whereas males did not show a significant preference, but in general more males preferred the compartment with the chemical cues of a female. Our results suggest that fire salamanders are capable to discriminate the sex of conspecific individuals based on pure chemical cues. We discuss our results in the light of the presence of dorsal glands in the males' cloaca of true salamander species, from which pheromones can be directly released onto the substrate.