The Roles of the Main Olfactory and Vomeronasal Systems in Prey Detection by Two Terrestrial Salamanders

Terrestrial salamanders of the genus Plethodon are among many vertebrates possessing both main olfactory and vomeronasal systems, which the Volatility Theory posits are for detection of volatile and soluble olfactory cues, respectively. Further recent work showing a high amount of convergence between the two olfactory subsystems at the level of the central nervous system suggests complementary or overlapping roles for them. This study examined the use of the olfactory subsystems in prey detection from the perspectives of behaviour and neurobiology. Red-backed salamanders, Plethodon cinereus, were observed in standardized behavioural assays with both volatile and soluble prey olfactory cues. Naïve salamanders showed an increase in nosetapping as well as a side preference in the presence of soluble and volatile prey cues when tested in a 22°C day/20°C night room. In a 15°C day /12°C night room, salamanders increased nosetapping in the presence of soluble prey cues. Salamanders showed a pattern of responses that differed based on their previous experience with the assay, as well as the temperature of the testing room. Attempts to study the neurobiology of olfactory function in Plethodon shermani were inconclusive up to this point, but future directions are discussed. This study shows the importance of olfaction in prey detection by salamanders and that prey searching behaviour is exhibited in the exclusive presence of olfactory cues.