Intra- and inter-litter variation in life-history traits in a population of fire salamanders (Salamandra salamandra terrestris)

Abstract

We examined intra- and inter-litter variation in larval life-history traits in relation to maternal weight and date of larval deposition in a population of fire salamanders Salamandra salamandra terrestris in north-western Switzerland. We also examined whether the timing of larval deposition by female fire salamanders is an adaptive strategy to the changing conditions of a temporary brook. Litters differed in mean weight at birth, weight at metamorphosis, and duration of the larval period. Mean weight at birth tended to be larger in litters deposited later in the season than in those deposited earlier. Large neonates reached metamorphosis more rapidly than small ones. A short larval period resulted in a small size at metamorphosis, indicating a fitness trade-off between duration of the larval period and size at metamorphosis. Within litters, successively-born larvae tend to decrease in body size, especially in litters with a relatively large variation in weight at birth. The results suggest that environmental factors such as floods or drying out of the brook may influence the timing of larval deposition.