The relative roles of natural selection and direct environmental induction, as well as of natural selection and genetic drift, in creating clinal latitudinal variation in quantitative traits have seldom been assessed in vertebrates. To address these issues, we compared molecular and quantitative genetic differentiation between six common frog (Rana temporaria) populations along an approximately 1600 km long latitudinal gradient across Scandinavia. The degree of population differentiation (QST 0.81) in three heritable quantitative traits (age and size at metamorphosis, growth rate) exceeded that in eight (neutral) microsatellite loci (FST = 0.24). Isolation by distance was clear for both neutral markers and quantitative traits, but considerably stronger for one of the three quantitative traits than for neutral markers. QST estimates obtained using animals subjected to different rearing conditions (temperature and food treatments) revealed some environmental dependency in patterns of population divergence in quantitative traits, but in general, these effects were weak in comparison to overall patterns. Pairwise comparisons of FST and QST estimates across populations and treatments revealed that the degree of quantitative trait differentiation was not generally predictable from knowledge of that in molecular markers. In fact, both positive and negative correlations were observed depending on conditions where the quantitative genetic variability had been measured. All in all, the results suggest a very high degree of genetic subdivision both in neutral marker genes and genes coding quantitative traits across a relatively recently (< 9000 years) colonized environmental gradient. In particular, they give evidence for natural selection being the primary agent behind the observed latitudinal differentiation in quantitative traits.

The highest altitude recorded for an amphibian in Europe (west of the Caucasus) is 2965 m. It refers to the "lacs de Cambalès" according to an old reference. However, these lakes are all situated below 2600 m, while the altitude corresponds exactly to that of the summit of the Pic de Cambalès. We undertook an almost complete survey of ponds in a 2.5 km radius from the Cambalès peak, and complemented these data by fieldwork in a larger portion of the Central Pyrenees. Based on our observations in a total of 325 lakes and ponds we conclude that no water bodies above 2800 m exist in the Cambalès area, and that no water bodies above 2600 m are populated by Rana temporaria. The highest amphibian record was that of a single R. temporaria specimen at 2569 m, while the highest reproducing population was found at 2516 m. Highest records of other amphibians were 2516 m (Alytes obstetricans), 2160 m (Bufo bufo), 2259 m (Euproctus asper), and 2142 m (Salamandra salamandra). The presence of ice-free water bodies during a sufficient amount of time for larval development is probably the limiting factor for elevational distribution of Pyrenean amphibians, and the adequate conditions are usually not met above 2500 m in this massif. In contrast, in the Alps, ponds at higher altitudes are often protected by much higher surrounding peaks, which leads to higher elevational occurrence of amphibians. The Italian Laghi di Tre Becchi (up to 2742 m) are therefore the highest locality of a reproducing anuran population in Europe west of the Caucasus.

Genetic differentiation of Rana  temporaria from  the Pyrenean and Cantabrian mountains in Spain was studied by means of allozyme electrophoresis. 24 loci were analysed in 104  specimens  from  15  populations:  nine  populations  from  the  Pyrenean  massif,  five populations from  the area of  the Cantabrian mountain chain (regions of Galicia, Asturias, and Basque Country), and one population from Germany. Three distinct clusters were distinguished by  phenetic  analysis:  (a)  the  Pyrenean  samples  and  the  single  population  from  the  Basque Country,  (b)  the  populations  from  Galicia  and  Asturias)  and  (c)  the  German  population. Ordination  (PCA)  resulted  in one principle  component  (PC1)  that  separated Cantabrian  from Pyrenean populations, and in a second one (PC2) that separated the single German population from the Iberian ones. PC1 indicated introgression that was corroborated by west-east clines in several  alleles  along  the Cantabrian  chain. The  rather  clear  separation  of  the Cantabrian  and Pyrenean  clusters  (mean  genetic  distance  0.121)  suggests  that  two  genetically  different subspecies  of  R.  temporaria may  be  distinguished  in  Spain.  The  absence  of  fixed  allelic differences between populations refutes recent hypotheses of  the existence of syntopic sibling species  within  R.  temporaria  in  Spain.  Biogeographically,  the  Pyrenean  and  Cantabrian populations  possibly  originated  in  two  separate  colonisation  events  starting  from  different glacial refuges. The strong morphological differentiation of Pyrenean R. temporaria populations is not paralleled by genetic divergence, and may better be explained by ecological factors such as climate, altitude and vegetation.

The aim of this study was to bring new information regarding the feeding of two amphibian species, Rana arvalis (moor frog) and Rana dalmatina (agile frog), in a forest habitat (Livada Plain, Romania). We have focused our attention upon the trophical spectrum variations that occur, depending on the species and the studying period. We noticed an increased diversity of prey taxa in the stomachal contents of the agil frog. The bugs, spiders and butterfly larvas are the most important prey for both species. There is an increased high mobility prey taxa amount (flying insects for instance) only in the agile frog's stomachal contents. We'd like to emphasize the fact that both species were hunting in terrestrial habitat.

In general, amphibians are known to exhibit a higher degree of population subdivision than any other major animal taxa, but large-scale population genetic surveys of widely distributed species are still scarce, especially in the Eurasian continent. Using microsatellite markers and mitochondrial DNA sequences, we investigated the large-scale population genetic structure of the common frog (Rana temporaria) — one of the most widespread amphibians of the Palearctic region. Analyses of cytochrome  b sequences revealed evidence for two distinct lineages inhabiting western and eastern parts of Europe. The separation of these lineages c. 700 000 years ago may have been induced by the onset of the Middle Pleistocene continental glaciations. Analyses of the variability of microsatellite loci within each of the clades revealed evidence for evolution of a high degree of population subdivision (FST ∼ 0.23) even in northern Fennoscandia, colonized less than 10 000 years ago. The high level of substructuring is puzzling in the face of an apparently high dispersal capacity, as evidenced by the rather rapid recolonization of northern Europe. This suggests that processes other than restricted dispersal capacity need to be explored as explanations for the high degree of population subdivision in amphibians. The colonization of northern Europe has been accompanied by loss of genetic variability as evidenced by decreasing levels of intrapopulational genetic variability in microsatellite loci from south to north across Europe.

Starch gel electrophoresis and morphometric characters were used to assess the geographical variation between 14 populations of the moor frog, Rana arvalis, from northern and southern areas in Central Europe. Six of the 13 screened allozyme loci were polymorphic (95% criterion). No fixed difierences in allele composition between the two regions were found. Some of the alleles were region specific. Genetic variability as measured by expected heterozygosity (He) and number of alleles per locus was significantly lower in the southern samples than in northern ones (He=0.104 and He=0.156, alleles/locus = 1.6 and 1.8 respectively). This is interpreted as a consequence of the difierent past history of these two groups during the Pleistocene. Population subdivision, as measured by FST, was substantial (0.124 and 0.078 for the southern and northern group, respectively); 59.9% of the between-locality variation is attributed to this division into two geographical groups. Isolation-bydistance was detected by significant negative correlation between the estimate of gene flow (log M) and log (geographical distance) only for the southern population groups. This indicates that the northern populations have recently recolonized their contemporary distribution area. The mean genetic distance between the northern and southern group of populations was DN = 0.062. Despite the relatively low genetic distance between them, the two population groups form two distinct clusters in the maximum likelihood (ML) tree. Discriminant analysis on 11 size adjusted body measurements showed considerable overlap between populations from difierent geographical areas. An isolated Romanian Reci population which genetically belongs to the southern group of populations was morphologically situated in an intermediate position between northern and other southern populations.

The objective of our study was to bring data upon the feeding of Rana lessonae, Rana arvalis from Reci region, Covasna County. We watched at the trophic spectrum of this two Rana species the variation depending on species, sex, habitat and diurnal activity. The feeding of moor frogs is more intense in twilight period. The largest diversity of preys was presented in the stomach contents of Rana lessonae samples captured from the pool. The females both of the two Rana species eat a greatest variety of preys vis a vis the males. Only Rana lessonae captured from the permanent pool present in stomach contents a relatively high number of aquatic preys.

The objectives of the current study were to  identify, in detail, the distribution of the largest moor frog populations from the Ier Valley  region and to assess the zones that represent important habitats and present measures for  their protection. Our study was conducted from March to October during the years 2001-2003. We identified 49 populations of Rana arvalis in the Ier Valley area. Most of these populations can be considered distinct, isolated from each other, apart from a few exceptions. This fact increases their regional chance of extinction. The Rana arvalis populations in the studied area occupy very different habitats. Only a few of these habitats can be considered natural biotopes. As a result of intense dry out of the swamps in the Ier Valley area, the populations of Rana arvalis had reduced in atypical smaller sized habitats, which  had a limitating effect on the size of these populations. Small numbers of moor frogs were found in most sites surveyed (less then 6 specimens / site / visit) in the region. We were able to calculate quantitative population assessments for five populations. The largest population was found near Andrid, with 675 ±57 adult specimens, making this one of the largest known population of Rana arvalis in Romania. The second significant population was estimated to be 354 ±25 individuals and it was located near Resighea. The other populations’ sizes were estimated at fewer than 200 adults. We consider the protection of the large breeding populations of Rana arvalis in the Ier Valley area to be a priority, by managing both the breeding and foraging habitats. The potential for the biggest moor frog populations to be part of a single infrastructure is discussed.