AbstractAspects of thermal ecology and reproductive cyclicity are compared in two populations of the dice snake (Natrix tessellata), a semi-aquatic natricine species widely distributed across Europe. One population was studied near Leibnitz, Styria (south-eastern Austria), and the other one was studied in the Mounts of Tolfa near Rome (Latium, central Italy). The climate was strongly colder in the Austrian than in the Italian site. Snakes of both populations were similar in various traits, including average body temperature, higher mean body temperature of gravid than non-gravid individuals, significantly higher substratum temperatures selected by gravid than by non-gravid individuals, trends of relationships between body, air and substratum temperatures, average length of reproductive females, and average preparturition mass of reproductive females. However, Austrian snakes were found in water significantly less often than their Italian conspecifics (although in both populations nearly all individuals occurred close to water bodies), and showed a lower frequency of reproduction (biannual rather than annual) than Italian ones. The presented data are discussed in the light of suboptimal occupation of the colder area by Austrian snakes, and conservative rigidity of natural history and ecological traits of such a widespread species as N. tessellata.
Thermal ecology and activity patterns of the lizard community of the Restinga of Jurubatiba, Macaé, RJ