Amphibia-Reptilia 29 (2008): 405-412 The large invasive population of Xenopus laevis in Sicily, Italy

Abstract. The worldwide spread of invasive species is considered to be one of the main causes of global amphibian declines and the loss of biodiversity in general. The African Clawed Frog, Xenopus laevis, shows a strong ability to establish populations and invade various geographic regions. In 2004 X. laevis was found in Sicily for the first time. The Sicilian population is probably the largest in Europe with a range of about 225 km2 in an area characterized by numerous agricultural ponds. This high density of ponds has potentially facilitated the dispersal of X. laevis. The frogs can move far from rivers or watercourses by utilizing the ponds as suitable “islands”. The analysis of their diet shows that the aquatic larvae of nektonic insects comprise the major portion in terms of mass while small planktonic crustaceans are the most numerous component. There is a significant difference between the diet of adults and juveniles