FOOD-HABITS OF THE GREEN LIZARD, LACERTA-BILINEATA, IN CENTRAL ITALY AND A RELIABILITY TEST OF FECAL PELLET ANALYSIS

Food habits of the green lizard (Lacerta bilineata) were studied in so me Mediterranean sires of the vicinities of Rome (Latium, central Ital y), by means both of stomach dissection of individuals found already d ead in the held and faeces analysis of living individuals. The taxonom ic diet composition of the lizards was accurately described by both me thods, thus demonstrating the reliability of faecal pellet analysis as an non-cruel method to study lizard diets. However, by using the faec es analysis technique, ic is difficult to measure the exact food intak e rate (items/unit of time) as well as the size distribution of prey i ngested by lizards. There was a remarkable ontogenetic a change in che taxonomic diet composition of green lizards: adults essentially consu med beetles and isopods, whereas juveniles fed mainly upon orthopteran s, spiders, and Rhynchota. Cannibalism and predation upon small verteb rates (lizards) were very rare events. It is suggested that (i) age-re lated differences in microhabitat frequented could explain the dietary differences between young and adult lizards due to different availabi lity of the various prey categories in the various microhabitats, and that (ii) adults and juveniles partition their habitats to reduce intr aspecific interference competition.