Detection of non-consumptive effects of predation and intraspecific aggression in fire salamander larvae: Environmental issues

The identification of injury causes may reveal important insights on the factors that influence intra and interspecific predation pressures. In this study we evaluated the proportion of injuries occurring in fire salamander larvae (Salamandra salamandra) in caves and epigean springs to understand the factors determining non-consumptive effects that may affect larval survival. We surveyed 25 sites (13 cave pools, 12 spring pools) during the day. We applied two consecutive removal samplings to collect fire salamander larvae and examined every removed larva to detect if it had injuries and we evaluated the proportion of the injured larvae on the total number of collected larvae. For each site we recorded different environmental variables including predator occurrence and prey density. The proportion of injured larvae was significantly linked only to predators occurrence. Our results show that interspecific predation pressure is a major source of non-consumptive effects that may affect larval survival Overall, our study underlines the role that environmental features may play on the non-consumptive effects of selective pressures that affect larval survival. Predator occurrence determines the levels of non-consumptive effects and larval survival across their developmental cycle. These results deriving from a field survey could furnish useful insights for further experimental studies.