Patterns of variation in dietary composition among four populations of Alpine salamanders (Salamandra atra prenjensis)

What is it about?

One important element that can change in the wake of population fragmentation is a species’ trophic biology (feeding ecology). Low food in habitat patches may drive top predators to extinction, with cascading effects on meso-predator populations and lower trophic levels. Consumers may adjust by shifting prey use and preferences, or by becoming more picky or more catholic, causing effects on niche width and positioning. Moreover, variation between individuals revealed an important element defining aspects of populations' feeding ecology. In this work we explored feeding patterns in four isolated populations of alpine salamanders (Salamandra atra) scattered across the Dinarides. All populations showed an equally wide dietary span that is among the largest reported for terrestrial salamanders. However, the amount of ingested prey is rather low compared to other salamander species; the quantity of consumed prey did not differ among populations but younger individuals fed more than adults. The bulk of diet consisted of beetles, spiders, snails and millipedes; except for beetles, such prey was also preferred together with centipedes and isopods. This suggests that salamanders prefer slow and bigger prey rather than fast and smaller, possibly due to their clumsy feeding style. Individuals revealed specialized on certain prey although this may reflect the fact that they were foraging in a patch of habitat, or period of time, particularly rich in some prey type.

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