TAIL AUTOTOMY AND EXTINCTION IN MEDITERRANEAN LIZARDS - A PRELIMINARY-STUDY OF CONTINENTAL AND INSULAR POPULATIONS

Tail autotomy is one of the main anti-predator mechanisms of lacertid Lizards, but it has bean predicted that it is only retained in its ful l capacity when its benefits exceed its costs (Arnold, 1988). To test this hypothesis, ease of tail shedding was examined in a number of con tinental and insular lacertid lizard populations, each of which showed a different shedding capacity. Tails are shed more easily in those co ntinental and insular populations where there is a greater probability of predation. In insular populations not subjected to strong predatio n, the tail tends to be retained. The relationship of these findings t o insular Mediterranean lizard populations and to the extinction of th e Balearic lizard. Podarcis lilfordi are discussed.