Chemosensory discrimination of conspecifics in the juvenile yellow-spotted river turtle Podocnemis unifilis

Abstract

Chelonians are very promising models to explore the role of chemical communication in social contexts. However, it still remains unknown how chemical signals may influence most behavioural patterns in turtles. In this study, we examined whether juvenile yellow-spotted river turtles (Podocnemis unifilis) use chemical cues released into water by other conspecifics to orientate towards them. To test our hypothesis, we compared the behavioural response (i.e., activity level and latency time) of juveniles when exposed to chemical stimuli obtained from other conspecifics (i.e., other juveniles and adult females), as compared to their response in clean water (i.e., the baseline). The results obtained in the study showed that juvenile P. unifilis increased their activity in response to chemical cues of female adult conspecifics. These findings suggest that juvenile turtles may chemically orientate themselves towards adult females during migratory processes. Efficient detection of conspecific chemical cues by juveniles is necessary for particular individuals to aggregate before migrating to habitats with more abundant food resources. Our study provides a framework for future research that should disentangle the role of chemical cues in mass migration of freshwater turtles.