Interpopulational variation in reproductive cycles and activity of the water snake Liophis miliaris (Colubridae) in Brazil

This study reports on aspects of reproduction in the water snake Liophis miliaris from four regions in Brazil: (1) northern coastal Atlantic forest, (2) southern coastal Atlantic forest, (3) northern inland Atlantic forest; and (4) southern inland Atlantic forest. In the northern coastal Atlantic forest, where there is little climate variation, the reproductive cycle of this species is continuous, with vitellogenesis and oviposition occurring throughout the year. Newly hatched snakes are found mainly in January. In other regions the cycle is seasonal and related to warmer and rainy periods, with vitellogenesis and oviposition occurring mainly from September to February. Hatchlings are more abundant from February to April, at the end of the rainy season. In the northern Atlantic forest newly hatched snakes have smaller body sizes than in the other regions. Sperm production seems to occur throughout the year in all regions, and where reproduction is seasonal, mating seems to be disassociated from vitellogenesis, suggesting that sperm may be stored by females over the winter. Females with oviductal eggs did not feed, whereas those ones with secondary vitellogenic follicles fed more frequently than non-reproductive females. In all regions, the activity pattern of adult Liophis miliaris seems to be related to reproductive cycles and climate variation.