Is the reaction to chemical cues of predators affected by age or experience in fire salamanders (Salamandra salamandra)?

Abstract

Predation is one of the strongest forces driving natural selection. Predator success reduces future prey fitness to zero. Thus, recognition and avoidance of a potential predator is an essential fitness-relevant skill for prey. Being well equipped in the predator-prey arms race is highly adaptive. In this context we tested whether age and/or potential experience of fire salamanders (Salamandra salamandra) affected their behaviour towards the chemical signature of a potential predator. We evaluated the space use of salamanders in a test arena with a shelter containing chemical cues from a predator (i.e., a rat) and a clean shelter. Our results demonstrate that naïve subadult fire salamanders do show a significant behavioural reaction towards rat odour. However, they do not avoid the chemical cues of the potential predator, but instead have a significant preference for the shelter with rat faeces. In contrast to this, both the naïve adult and wild-caught adult fire salamanders showed neither a preference nor an avoidance of rat scent. These results could suggest a role of age in odour-based predator recognition in salamanders. Similarly, predator recognition through chemical cues could be more important early in life when the young fire salamanders are more vulnerable to predatory attacks and less important in other life stages when salamanders are less subjected to predation. In conclusion, future studies considering wild-caught subadults should disentangle the importance of previous experience for predator chemical recognition.