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1

Validation of two new total body electrical conductivity (TOBEC) instruments for estimating body composition of live northern red-backed voles Clethrionomys rutilus

100%
Zuercher G. L., Roby D. D., Rexstad E. A.
Acta Theriologica
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1997
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tom 42
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nr 4
Total body electrical conductivity (TOBEC) is a method for non-destructively esti­mating body composition. We sought to monitor seasonal changes in total body fat in northern red-backed voles Clethrionomys rutilus (Pallas, 1779), a microtine (10-45 g). We validated two new TOBEC instruments: the SA-3000 by EM-SCAN Inc. and the ACAN-2 by Jagmar Inc. Both instruments explained 94% of the variation in lean body mass and total body water. However, accuracy of fat estimates generated from lean mass predictions was poor for both instruments (± > 100%). Two instrument-specific multiple regression models and a TOBEC-free multiple regression model were used to estimate total body fat. All three improved the ability to predict total body fat in C, rutilus. These two TOBEC instruments can not be used to measure changes in total body fat of individual C. rutilus due to the small amount of fat reserves and lack of seasonal variation.
2

Cytogenetic homeostasis and population density in red-backed voles Clethrionomys glareolus and C.rutilus in central Siberia

84%
Dmitriev S. G., Zakharov V. M., Sheftel B. I.
Acta Theriologica. Supplement
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1997
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nr 04
We examined frequency of chromosome aberration in somatic cells in sympatric growing populations of bank vole Clethrionomys glareolus Schreber, 1780 and ruddy vole C. rutilus Pallas, 1779 in central Siberia (Yenisei river island, 62°N, 89°E) from 1992 to 1994. The island was reinhabited from the mainland populations in 1992 after abnormally high flooding which eliminated the previous island populations of the species. The frequency of chromosome aberration increased parallel to the population density of island populations of both species in 1992-1994. In the mainland population of C. rutilus in 1994, the year of low density for this highly cyclic population, significantly lower frequency of chromosome aberration was found as compared with an island population characterized by high density in this year. These results are interpreted as a disturbance of cytogenetic homeostasis indicating an alteration in an organism's condition in the overcrowded populations of both species under study.
3

Non-metric variation in red vole populations within the East-Ural Radioactive Track [EURT] zone

84%
Vasilyev A. G., Vasilyeva I. A.
Acta Theriologica. Supplement
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1995
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nr 03
Ecological monitoring of red vole Clethrionomys rutilus (Pallas, 1778) populations, carried out for two years (1992-1993) in the Sverdlovsk region near Kamensk-Ural'ski, revealed an increase of morphological diversity in terms of non-metric skull traits along the axis of the East-Ural Radioactive Track (EURT). In the population affected by radioactive contamination, frequencies of non-metric skull traits deviated significantly from those in two control populations located beyond the EURT boundaries. The deviations were not related to particular environmental factors varying among the years of our study, which implied a genetic basis of non-metric differentiation. We suggest that the observed increase of phenotypic malformations within the EURT zone has been caused by the permanent impact of low doses of radioactive contamination, leading to an accumulation of minor mutations and to disurbances in regular ontogenetic development of the red vole.
4

Geographic localization of a contact zone between bank voles Clethrionomys glareolus with distinctly different mitochondrial DNA

84%
Tegelstrom H., Jaarola M.
Acta Theriologica
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1998
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tom 43
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nr 2
Fennoscandian bank voles Clethrionomys glareolus, Schreber 1780 show two dis­tinctly different mitochondrial DNA (mtDNA) lineages, one occurring in the southern and central, and another in the northern parts. The mtDNA of northern bank vole populations is very similar or identical to that of the northern red-backed vole C. rutilus, Pallas, 1779 and the presence of this mtDNA lineage among northern bank voles probably is a consequence of hybridisation between the two species, To localise the geographic position of the contact zone between bank voles with the two types of mtDNA, we have analysed a transect through the area were both types of mtDNA have been found. The contact zone coincides with two other intraspecific mammalian contact zones, and is adjacent to a third zone. These zones constitute "suture zones", reflecting secondary contact between populations derived from separate glacial refugia and with synchronous timing of secondary contact. The width of the bank vole contact zone, approximately 30-60 km, is consistent with the hypothesis that it is a neutral contact zone. However, because mtDNA may penetrate reproductive barriers easier than nuclear genes it is necessary to analyse the zone with nuclear markers before drawing any definite conclusion regarding the extent of introgression.
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