Trophic niche of cave populations of Speleomantes italicus

Abstract

This paper investigates the trophic niche of a poorly studied cave salamander, Speleomantes italicus. We examined Central Appennine hypogean populations that inhabit seven caves situated in three limestone areas in Umbria Region (Italy). Adults displayed feeding activity from May to December and the Vacuity Index analysis revealed a discontinuous trophic activity pattern throughout the year related to prey phenology. According to the qualitative analysis of the trophic spectrum, the populations in question can be defined as euryphagous, while the quantitative analysis (in terms of number and volume of preyed taxa) revealed a specialist strategy with a clear preference towards Diptera Limnobiidae. Both sexes presented similar trophic niche breadth and a high diet overlap, showing no intersexual differences. The hypogean populations of S. italicus, similarly to S. strinatii, showed a narrower trophic niche than epigeans of the same species, probably due to the limited food availability in the cave habitat.