Specialization is typically inferred at population and species level but in the last decade many authors highlighted this trait at the individual level, finding that generalist populations can be composed by both generalist and specialist individual. Despite hundreds of reported cases of individual specialization there is a complete lack of information on inter-individual diet variation in specialist species. We studied the diet of the Italian endemic Spectacled Salamander (Salamandrina perspicillata), in a temperate forest ecosystem, to disclose the realised trophic niche, prey selection strategy in function of phenotypic variation and inter-individual diet variation. Our results showed that Salamandrina is highly specialized on Collembola and the more specialized individuals are the better performing ones. Analyses of inter-individual diet variation showed that a subset of animals exhibited a broader trophic niche, adopting different foraging strategies. Our findings reflects the optimal foraging theory both at population and individual level, since animals in better physiological conditions are able to exploit the most profitable prey, suggesting that the two coexisting strategies are not equivalent. At last this species, feeding on decomposers of litter detritus, could play a key role determining litter retention rate, nutrient cycle and carbon sequestration.

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Information on the trophic ecology of the Alpine salamander, Salamandra atra, is scattered and anecdotal. We studied for the first time the trophic niche and prey availability of a population from an area located in Italian Dolomites during the first half of August. Considering that S. atra is a typical nocturnal species, we collected food availability separately for diurnal and nocturnal hours. Our aims were: (i) to obtain information on the realized trophic niche; (ii) to provide a direct comparison between trophic strategy considering only nocturnal preys or considering all preys; (iii) to study trophic strategy of this species at the individual level. In two samplings nights we obtained prey from 50 individuals using stomach flushing technique. Trophic strategy was determined using the graphical Costello method and selectivity using the relativized electivity index. During the short timeframe of our sample, this salamander showed a generalized trophic strategy. The total trophic availability differed significantly from nocturnal availability. Interindividual diet variation is discussed in the light of the optimal diet theory. Finally, we highlighted that considering or not the activity time of the studied taxon and its preys may lead to a conflicting interpretation of the trophic strategies.

Recent studies suggest that many organisms actively colonize the subterranean environment to avoid climatic stress, exploit new ecological opportunities and reduce competition and predation. Terrestrial salamanders are known to colonize the more stable subterranean habitats mainly to escape external climatic extremes, while the role of predation avoidance remains untested. To better understand the importance of predation, we used clay models of the cave salamander Speleomantes strinatii to compare the predation occurring in woodland and subterranean habitats. Models were positioned in three forests and in three caves in NW Italy. One-hundred eighty-four models were retrieved from the field and 59 (32%) were attacked by predators. Models were attacked on their head more often than expected by chance and, therefore, were perceived by predators as real prey items. In the woodlands, clay models showed a four-time higher probability of being attacked in comparison to caves, suggesting a different level of potential predation risk in these surface habitats. These findings are one of the first experimental evidences that, in terrestrial ecosystems, predation avoidance may contribute to the salamander underground colonization process.