ИСТИНА

Body length, age composition and morphological traits were studied in breeding adult Rana arvalis from three different regions of Russia. Sexual size dimorphism was non-significant in Tomsk region population with minimal duration of activity season. The males of two other populations were significantly larger than females. These differences were not connected with among-population variation in body length as the significantly larger sizes of both sexes were revealed in population from Moscow region and the smaller sizes – in Bryansk and Tomsk regions. The highest growth rate in both sexes was in Bryansk region with maximal duration of activity season. However, the maximal average values of body size in Moscow region corresponded to maximal average ages in this population. The significantly higher values (both absolute and relative to body length) of extremities and some parts of head in males indicate on its apparently importance as adaptation. The morphological peculiarities in each population were expressed as sexual dimorphism of different traits in different populations and did not correspond to among-population differences in body length. The higher degree of similarity in set of studied morphological traits was revealed between two most remote populations, that were characterized by similar body sizes, however.