Trophic habits of Muscardinus avellanarius (Mammalia Gliridae) as revealed by multiple stable isotope analysis

Multiple stable isotope analysis was used to investigate the diet of the common dormouse Muscardinus avellanarius in a mixed Mediterranean forest. δ13C and δ15N values of dormouse tissues compared to those of the vegetal and animal sources available in the area showed that the isotopic composition of both adult and juvenile M. avellanarius could be explained by a mixture of vegetal and animal organic matter. The isotopic composition of the assimilated nitrogen was mostly explained by the organic matter from flora. Among the vegetal components, flowers of Fagus silvatica, Quercus robur, and the rarer Crataegus oxyacantha, berries of Ilex aquifolium and acorns of Q. robur were found in the adult diet, while juveniles relied mainly on flowers of F. silvatica and acorns of Q. robur. Organic matter from eggs of passerines (Parus caeruleus and P. major) sharing nest-boxes affected the carbon isotopic signals in the assimilated fraction. The common dormouse in the mixed holly forests of the northern Sicily feeds primarily on the vegetal species which are abundant in its habitat. However, the diet of this small arboreal mammal cannot be fully characterised without considering the contribution of animal organic matter represented by bird eggs.