Search

In this review, we describe karyotypic, morphological, and genetic structuring of population in the common shrew Sorex araneus (Lipotyphla, Mammalia), and try to explain some unclear and contradictory aspects of this structuring on the basis of population approach. The subdivision of this species into more than 76 parapatric chromosomal races does not correspond to its morphological and genetic structuring. Chromosomal hybrid zones are formed in the areas of contact between the races. The frequency of interracial F1 hybrids is low in nature, but we have shown that mating between different races in captivity occurs quite readily, although the postnatal survival of hybrids is reduced. We suggest that this species is subdivided into relatively small populations characterized by the unity of functioning, which is ensured by the predominant dispersal of individuals from each of the populations within their population space. It should also be emphasized that the main provisions set forth by Stanislav S. Shvarts in his conceptual monograph The Evolutionary Ecology of Animals are still relevant today. [ABSTRACT FROM AUTHOR]

Karyotyping of the common shrews Sorex araneus from the poorly studied region of the Northwest of Russia revealed the belonging of individuals to two chromosomal races, Lemi and St. Petersburg. The Lemi race, previously known only from Finland, was discovered for the first time on the territory of Russia and thus replenished the list of S. araneus chromosomal races that are distributed within the Russian part of the species range (27 races out of 74 known in the whole species range at the moment). The studied individuals showed a high level of chromosomal polymorphism, caused by Rb translocations. [ABSTRACT FROM AUTHOR]

The significance of smell marks of conspecifics for the spatial distribution of common shrews was studied. The existence of two groups of individuals, which differ in their reaction to the smell of a conspecific, was shown. Individuals with different reactions were shown to have reliable differences in the sizes of the areas visited by them, the mutual location of their plots, and the percent of activity combined with the activity of the neighbor. The significance of such differences in reactions for the formation of the social system of shrews is discussed. [ABSTRACT FROM AUTHOR]

The home range of resident animals is considered as 'familiar area' including a 'foraging area.' It has been revealed that the activity of an average animal unit in the 'foraging area' could be approximated by normal distribution. Estimation of activity distribution in the 'familiar area' (beyond the 'foraging area') was impeded by means of marking since it might be difficult to record distant movements, and the method does not provide an essential body of data. In the case of the common shrew Sorex araneus, the 'familiar area' was estimated using pitfall as animals evade them in the known areal. The 'foraging area' radius of the average shrew was taken to be 30 m (95% of the animal unit activity), the radius of 'familiar area' was within the range of 180-240 m. The 'foraging area' was expected to provide the animal with vital resources, and the 'familiar area' reflects its need for exploratory activity. [ABSTRACT FROM AUTHOR]

Many publicists and political activists have been fond recently of ending their presentations with a dramatic statement about the "unpredictable consequences" that would follow if the commands of their particular oracle were not promptly adopted and applied, or if the course of events took a turn they had not considered. We think it superfluous to elaborate the obvious thesis that an honest analysis must necessarily include an examination of the totality of probable paths of development of the situation, and especially those whose possible realization is for some reason extremely undesirable. The position of an ostrich that hides its head in the sand when it sees a real or apparent danger leads only to an inadequate perception of complex processes and, in the final analysis, misinforms those who make decisions and disorients the public about the foreseeable future. [ABSTRACT FROM AUTHOR]