Evolutionary novelty in chemical signalling is linked with chemosensory behaviour in close Liolaemus lizard species (Iguania: Liolaemidae)

Evolutionary changes, associated with the gain or loss of traits, can occur in signal-emitting and signal-detecting organs. Related functionality generally accompanies these changes; however, in some cases there are mismatches and evolutionary innovations do not show an indication of functional advantages. Due to this, the relationship between evolutionary changes and the functionality of sensory organs remains unclear. Lizard species belonging to Liolaemus lineomaculatus section present fast evolutionary state transitions associated with the gain or loss of precloacal pores (chemical signalling glands). In this group, precloacal pores configuration includes species where only males have pores (Liolaemus attenboroughi-ancestral state), where both sexes lack of them (L. kolengh male-loss), and species where both sexes have pores (L. zullyae, representing a female-gain). Here, we test the relationships between evolutionary changes of signal-emitting glands with different chemical and visual behaviours. We conducted behavioural trials in three species belonging to the Liolaemus lineomaculatus section: L. attenboroughi, L. kolengh, and L. zullyae. We measured individuals' chemical and visual responses to different social scents and to conspecific visual stimuli. Results showed the presence of different social scents recognition ability in both male-only and female-gain species, whereas male-loss species showed no behavioural differences among the chemical trials. Lizards exhibited few responses in the visual trials, although the species with pores used chemo-sensorial sense in the visual trials, while male-loss species showed differences in visual displays in the presence of conspecific visual stimuli. These results suggest a link between evolutionary novelties of chemical secretory glands and chemical recognition.