Feeding Ecology of the Non-native Italian Wall Lizard in Urban Southern California

The Italian wall lizard, Podarcis siculus, is an opportunistic, omnivorous, lacertid lizard native to Italy and the east Adriatic coast. Multiple introduced populations of this species occur in the Mediterranean region, and P. siculus was also introduced to an urban Southern California neighborhood in 1994. In this study, we looked at the feeding ecology of California P. siculus to determine what affects it is having on the flora and fauna of its new environment. We conducted field surveys to determine the current distribution of this population and obtained voucher specimens for gut content analysis. These analyses demonstrate dietary overlap with the native Western Fence Lizard, Sceloporus occidentalis, and Southern Alligator Lizard, Elgaria multicarinata, which also occur in this neighborhood. Few native lizards were observed sympatrically with P. siculus suggesting that direct competition could be causing localized declines of these native lizards. Our study also suggests that P. siculus may prey upon native lizards. Adult P. siculus were found to cannibalize smaller individuals, suggesting that predation of native lizards is likely.