The common wall lizard Podarcis muralis (Reptilia: Lacertidae) shows diverse food preferences and intraspecific difference: a study case from Bulgaria

The Common wall lizard (Podarcis muralis) has the largest range among the genus Podarcis. Although there are a number of studies on its diet, data on regional level remains insufficient, particularly from a purely ecological perspective. We investigated 194 individual faecal samples of P. muralis obtained from two localities in western Bulgaria with the aim of clarifying the composition of the trophic spectrum of the species, as well as the intra-population characteristics in terms of age and sex. In one study site we compared the realized trophic niche (prey items from the faecal pellets) with the fundamental (invertebrates collected via pit-fall traps exposure). We confirmed that P. muralis is an opportunist in terms of feeding and has a very wide trophic spectrum including several taxa, which have not been reported until now as a part of the species diet. We revealed differences in feeding behavior between subadults and adults, as well as between males and females Adults have higher diversity in the food spectrum compared to subadults. According to sexes, females have more varied diet. We also report for the first time for the species six cases of keratophagy. Also, we identified a relatively frequent occurrence of saurophagy (n=16), including in females and subadults, for which this phenomenon has not been recorded so far.