INFLUENCE OF CLUTCH DATE ON EGG AND HATCHLING SIZES IN THE ANNUAL CLUTCH OF LACERTA-SCHREIBERI (SAURIA, LACERTIDAE)

Clutch size and egg mass are not related in a mountain population of L acerta schreiberi. This endemic Iberian lacertid lays only one clutch (7-24 eggs) per year. Synchronicity among breeding females is related to a long incubation period, which leaves a short activity period for juveniles before their first wintering. The length of the incubation p eriod shows a strong relationship with environmental temperature. Vite llogenesis starts at the beginning of the activity season, and clutch size is related to female SVL. Clutch size corrected for maternal SVL is not correlated with egg mass and shows no variation among years. Ho wever, egg size and hatchling SVL show among-year and interindividual variation and are not related to female SVL or relative clutch mass. E gg mass is positively correlated only with the laying date. We suggest that clutch size depends only on stored lipids remaining after winter ing and environmental factors could be responsible for egg size variat ion during vitellogenesis.