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Interdependence among non-metric traits as well as their correlation with sex, age, and body size usually cause methodological problems in phenetic investigations. Based on data on four mammalian species (Microtus oeconomus, M. limnophilus, Lepus europaeus, Capreolus capreolus) studied by the author, and on data from the literature these problems were analyzed. Both the number and the coefficients of intercor- relations among traits were found to depend on sample sizes of individuals examined. They were larger in populations with progressive and faster body growth. The number of traits related to sex increased significantly with sex dimorphism across mammalian species. Age dependence of traits did not show a regular pattern within and among species. These results are discussed as to their implications for estimating morphological differentiation within and among populations.
Prey individuals representing the bank vole Clethrionomys glareolus and the field vole Microtus agrestis were presented in pairs to male and female least weasels Mustela nivalis Linnaeus, 1766 in the laboratory. The voles were placed in two randomly selected boxes out of 8 boxes, which were connected to an arena housing the weasel. For each trial we recorded the finding, killing and eating order of the two prey individuals. Mate weasels tended to kill bank voles before field voles, and female weasels preferred to eat the bank vole first. Both sexes selected juvenile bank voles as the first prey to eat.
The study of diet composition of the Montagu`s Harrier (Circus pygargus (L) in two distinct breeding populations in 1996 in Hrodna and Smarhon` districts in Western Belarus have found different occurence of small mammals: 72,6% (n=2034) for the population #1 and 85,0% (n=254) for the population #2. Main prey in both populations was represented by vole species Microtus spp.: 68,5% and 78,3% for populations #1 and #2 accordingly. Significant difference was found in share of birds, mainly ground-nesting Passerines (17,5% and 12,6% for the population #1 and #2 accordingly) and large grasshoppers Tettigonia sp. (6,4% and 0,4% accordingly). Other prey categories (mice, shrews, hares, eggs of birds, lizards, dragonflies, large beetles and frogs) did not form an important part of the diet of these populations. We believe that opportunistic hunting behavior of the Montagu’s Harrier (which can easy switch on seasonally or locally abundant and accessible prey) is one of the reasons why the species did not form any subspecies throughout its wide range.
Sixteen specimen of Microtus (Terricola) collected in subalpine meadows of the Pindos and Iti mountains were karyotyped. All 11 animals from the Pindos mountain had the same karyotype with 2n = 42, NF = 42. The individuals collected on Iti mountain had a karyotype with 2n = 40, NF = 42 characterized by a large pair of metacentric chromosomes. The two karyotypes were closely related and one might have derived from the other by a Robertsonian centric fusion/fission. In both karyo­types the X and Y chromosomes were large acrocentrics. The karyotypes of the voles studied were more similar to that described for M. (T.) thomasi than to the other species of Terricola known in Greece.
Small mammals were surveyed along a deforestation gradient in southern Gansu, China (2300-2600 m altitude), a high endemicity area for human alveolar echino­coccosis. Rodent distribution was assessed using removal trapping in six habitat types from timbered forest to farmland and villages, by index transects, and by the collection of specimens by local people, Species captured were 2 shrews: Anourosorex squamipes, Sorex sinalis-, 12 rodents: Eozapus setchuanus, Microtus limnophilus, Cricetulus long/- caudatus, Tscherskia triton, Apodemus agrarius, Apodemus draco, Apodemus penin- sulae, Micromys minutus, Mus muscitlus, Rattus noruegicus, Niviventer confucianus, Myospalax fontanieri\ and 1 lagomorph Ockotona thibetana. On the basis of trap success four rodent assemblages were recognized. Species richness decreases after deforestation, especially in the intermediate stage (scrubland-grassland).
Arrays of pitfalls and drift fences were deployed in five deciduous forest habitats in southcentral Pennsylvania to assess the characteristics, and temporal and spatial dynamics of forest small-mammal communities, and to determine the impact of precipi­tation, sampling method, and length of sampling period on perceived small-mammal abundance and community structure. Results revealed that soricid assemblages were more diverse and generally more abundant than rodent assemblages, which were dominated by the white-footed mouse Peromyscus leucopus. Precipitation dramatically increased the capture rates of shrews; the response was less pronounced in rodents. Individual species responded independently to precipitation. The response was more pronounced in three species of arvicoline rodents (Clethrionomys gapperi, Microtus pinetorum, and M. pennsylvanicus) than in P. leucopus, a sigmodontine. Comparisons of sampling with pitfalls and Museum Special snap-traps, with and without drift fencing, revealed that arrays of pitfalls with drift fences produced significantly higher capture rates for all small mammals, shrews, rodents, and P. leucopus, greater num­bers of species, and higher Shannon indices than other sampling methods, Comparison of the results of sampling for 3, 5, 7, and 10 days revealed that extending sampling to 7 or more days yielded significantly more species, higher Shannon indices, and greater numbers of individuals than sampling for less than 7 days.
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