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International audience; We describe the age structures of two neighbouring terrestrial salamander populations. The skeletochronological method was also used on larvae in utero and on new-born individuals. The age of adults was 8-24 years in population A, while males reached maturity at 3-5 years old and the youngest females were 6 years old in population B. Males and females from population B were also larger than those in population A. For the first time, lines of arrested growth (LAGs) were also found in the humerus of intra-uterine larvae and new-born individuals, indicating that young can spend up to 3 years in utero (population B) and up to 4 years (population A) before hatching. Growth of adults (fitted by the Bertalanffy model) also exhibited differences in growth coefficient (k) and mean asymptotic length (SVLmax) between sexes and populations. Local climatic conditions differed between the two areas of these populations and we hypothesize that the number of rainy days directly influences foraging during the short period of activity (< 3 months), leading to a delay in age at maturity, smaller length and growth rate, and increased gestation duration in the drier environment. The discussion is focused on proximate environmental influences on the variation of length and associated life-history traits in ectotherms, especially in terrestrial salamanders.

Life-history traits of Rana temporaria were studied in an alpine French population and in the literature. In the living frogs, mean adult body length was greater in females than in males. Sexual dimorphism in body length was 0.109 using Lovich & Gibbon's (1992) formula, but tended to decrease with age. Age of adult frogs was assessed by skeletochronology, and age distribution was not significantly different between the sexes (range 4–15 years in males, 5–12 in females). Adult survival rate was about 0.80 in both sexes. Once maturity was reached, the total expected longevity was 6.1 years in males and 5.5 years in females. Age and body length were positively correlated in both sexes. The growth coefficient (K) was 0.47 in males, and 0.55 in females, mainly reflected as faster female growth between metamorphosis and maturation. Growth rate generally decreased before sexual maturity was reached. On average, females matured 1 year later than males. Newly metamorphosed froglets averaged 16.1 mm. When combined with published data from 12 European populations of R. temporaria, the following general patterns emerge. Mean adult body length is significantly greater in females than in males, and mean body length at maturity shows the same trend. Variation in mean age at maturity and in longevity are considerable among populations, but there is no consistent trend of difference between the sexes. Body length and age are correlated between males and females, i.e. populations with long and old males also have long and old females. Mean adult body length, mean body length at maturity, age at maturity, and longevity all increase with decreasing activity period. Adults exposed to a short activity period grow slower but attain a greater final length. Sexual dimorphism in body length generally increases as activity period gets shorter. Polygons describing norms of reaction for maturation in an age–body length space are similarly oriented in both sexes, but with a wider range in age for females. This is due to an older age at maturity for females in populations with a short activity season. Mean age and length at maturity are significantly correlated in females, but not in males, partly supporting the hypothesis that this species has a flexible pattern of development. Observed patterns are compared with predictions from life-history theory, paying attention to all life stages and environmental variation.

Abstract Pelodytes punctatus est une espèce dont les biotopes de reproduction sont localisés en plaine principalement (90% des cas). De nouvelles données sur la phénologie de la reproduction ainsi que sur le type de milieu ont été collectées durant 6 ans sur 4 régions comprenant plus de 35 sites. La période de ponte principale survient au printemps mais on peut en observer une deuxième en automne dans le sud de la France. Les œufs sont fixés en cordons par les femelles sur les tiges de plantes aquatiques. Le succès de l'éclosion dépend de l'oxygénation de l'eau. La croissance larvaire est relativement rapide en conditions contrôlées (19°C ± 1°C) et les têtards se métamorphosent 40 à 60 jours après l'éclosion. Dans le sud, deux catégories de têtards sont observées en automne, les plus petits hivernent et se métamorphosent durant le printemps suivant.

Times Cited: 3; International audience; The pattern of genetic differentiation of the endemic alpine salamander, Salamandra atra, has been studied using amplified fragment length polymorphism (AFLP) from 11 populations throughout the range of the two currently recognized subspecies, atra and aurorae. Five different primer combinations produced 706 bands and were analyzed by constructing a phylogenetic tree using NJ and principal component analysis. Significant genetic variation was revealed by AFLP between and within populations but, our results show a lack of genetic structure. AFLP markers seems to be unsuitable to investigate complex and recent diversification. (C) 2003 Elsevier Inc. All rights reserved.

The total energy flux in an Amphibian was measured using a microcalorimetric technique throughout different stages of development. Simultaneous records of the individual activity (actography) allowed us to study circadian rhythms and their variations during ontogenesis. Acrophase of the energy exchanges take place at the beginning of the night in adults, tadpoles and juveniles of more than 9 months. However, there was a shift in the acrophase of the circadian rhythm in juveniles aged between 7 and 9 months. This could be an adaptation process which regulate competition within populations of the same species.

The present conduction calorimeter was assembled to study the thermogenesis of whole organs or little Vertebrates. It is constituted of three essential parts : one aluminium calorimetric block, two cylindrical cells in plexiglass of 60,80 or 100 ml volume, two flux plates : the sensitive elements which permit differential measurements on a chart recorder. The whole system is thermoregulated.

1. 1. Organs analysed were liver, tail muscles, serum of tadpoles living in groups or isolated. 2. 2. At the same stage of development, the grouped individuals are bigger and a significative difference exists between the percentage obtained in serum albumin of tadpoles living either in groups or isolated (20% to a maximum). 3. 3. In liver, there is an increase at certain bands in grouped tadpoles, such as fraction 10 whose mobility is similar to that of the serum albumin. 4. 4. There is very little quantitative variations in the tail muscles of tadpoles grouped and isolated at the level of fractions 1 + 2, 3 + 4, 6, 7, 9, 12.

In the anterior pituitary of Alytes obstetricans Tadpoles in premetamorphic stages, two cell types were localized by cytoimmunological techniques: orangeophilic cells secreting a prolactin-like hormone in the anterior and median region and erythrosinophilic cells secreting growth hormone in a more caudal situation. Both cells are more numerous and stimulated in grouped Tadpoles than in isolated ones.