Rattus rattus vs. Salamandra salamandra - videos

Predator-prey interaction is a major force driving natural selection. Yet, the effect of possible predators on aposematic species is largely unknown. Islands constitute excellent natural laboratories to investigate predator-prey coevolution due to their isolation and relatively simple biological communities. Here, I conduct a study evaluating the role of the exotic Rattus rattus as possible predator of the aposematic and toxic Salamandra salamandra. I used camera traps to investigate the response of R. rattus toward S. salamandra carcasses in two insular populations, Ons and San Martiño (NW Spain), which show a remarkable contrasting behavior (nocturnal vs. diurnal activity), and demographic and phenotypic differences. This study confirms R. rattus consumes S. salamandra despite its toxicity. The high number of salamanders consumed by rats throughout each island (90-100%) and the lack of other possible predator-prey interactions, suggests R. rattus as an efficient predator of S. salamandra in these insular environments, which exerts a high predation pressure on the small and diurnal population of San Martiño. Yet, the drivers underlying the behavioural and phenotypic differences in this population should be further investigated.