Social organization of the bank vole (Clethrionomys glareolus,Schreber 1780) and its demographic consequences: a model

Summary A unified model of social organization, spatial distribution, and demographic parameters in the bank vole was developed. It is based on social relations among females, among males and also between reproductive females and males. In the model, social status and reproductive condition of an individual depend exclusively on interactions with its nearest neighbours. A result of interactions between two neighbours remains local, i.e., it cannot affect other, more distant individuals. The simulated variables show similar trend and scatter as those found in a growing real population of the bank vole. The relevance of the model for theories of population dynamics is discussed.     

The long-term effect of cadmium exposure through food on the postnatal development of the bank vole (Clethrionomys glareolus Schreber, 1780)

Cadmium is well known for its toxicity to the animal body. However, its effect on pregnancy and the development of young animals is still not well understood. This study examined such effects, using bank voles captured from the wild to make the results closer to those which could be expected in the natural environment. One group of animals was fed 7 microg g(-1) cadmium in the food, a second 35 microg g(-1), and a third no cadmium, as a control. The concentrations of cadmium in the whole bodies of young bank voles were determined on the 3rd, 5th, or 10th day of life. The cadmium level in the bodies of animals exposed to 35 microg g(-1) of cadmium was significantly higher than in those from either the control group or the group receiving 7 microg g(-1) of cadmium, which did not differ from each other. The cadmium level did not change with animal age in any of the study groups. Concentrations of Zn, Cu, and Fe were also determined in the whole body of young animals, as cadmium is known to disturb the metabolism of these essential metals through antagonistic activity. Both Cu and Fe levels were negatively correlated with cadmium concentrations, while a positive correlation was found between zinc and cadmium in the young animal bodies. Also found was higher offspring mortality in the group receiving 35 microg g(-1) of cadmium in food. There was no difference in young animal body weight between the study groups.     

Patterns of host-parasite interactions between the nematode Heligmosomum mixtum (Schulz, 1952) and the bank vole (Clethrionomys glareolus Schreber, 1780)

Some aspects of the host-parasite interaction of the nematode Heligmosomum mixtum and the bank vole have been studied. The dependence of infestation on the host sex, age and weight, the seasonal and annual abundance dynamics are investigated. It has been found that the bank vole is the main host of H. mixtum; the distribution of H. mixtum abundances in the host population is described by a negative binomial distribution model. The greatest infestation is characteristic for mature bank voles; males are infected more heavily than females. Infestation with the nematode increases alongside with the host weight. Seasonal dynamics of the nematode abundance in a bank vole population appears as a curve with a maximum in January and a minimum in August; the infestation curve for 1-month-old animals captured from June through October has two peaks (in July and October), with a minimum in June. The number of parasites in the ecosystem over a long-term period changed synchronously with the host abundance. The synchronism in the host-parasite system dynamics is possible when the parasite has a short life span, and does not influence the host abundance.     

The use of arboreal runways by the woodland rodents, Apodemus sylvaticus (L.), A. flavicollis (Melchior) and Clethrionomys glareolus (Schreber)

The use of arboreal runways by the rodents, Apodemus sylvaticus, A. flavicollis and Clethrionomys glareolus , was investigated in the deciduous woodland of Woodchester Park, Gloucestershire, England. Longworth live traps were tied to horizontal and inclining branches of trees and shrubs up to 3 m. Arboreality was extensive in all three species, although less in C. glareolus than in either Apodemus species. There was no indication that A. flavicollis consistently used arboreal runways more than A. sylvaticus but the data suggest that the peak of arboreal activity of these congeners occurred in different seasons. In A. sylvaticus , males were more arboreal than females and adults were more arboreal than juveniles. In, 4. flavicollis , juveniles were trapped significantly more often on arboreal runways than adults. The reasons for, and the consequences of, arboreality in small rodents are discussed.     

Fertility of the post-partum bank vole (Clethrionomys glareolus)

Analysis of records of a bank vole breeding colony suggests that fertility is high immediately post partum, declines during established lactation and rises after weaning of young. Mating tests with lactating females and females whose young had been removed at birth showed that receptivity is reduced during lactation, although amongst the females which did mate there was no difference between lactating and non-lactating animals in the proportion which produced litters. However, average size of litters at birth was significantly larger for the lactating than for the non-lactating females. There is some evidence suggesting that this difference may arise after ovulation has occurred. Virgin females were no more receptive or fertile than lactating females.     

Influence of Social Conditions on Humoral Adaptive Immunity in Bank (Clethrionomys glareolus) and Gray-Sided (Clethrionomys rufocanus) Voles: An Experimental Study

Biology Bulletin - The effect of the population density on humoral adaptive immunity in bank (Clethrionomys glareolus) and gray-sided (C. rufocanus) voles has been studied. We used 20-, 40-, and...     

Adaptation of the bank vole (Clethrionomys glareolus Schreber) to conditions of biogeochemical province with abnormally high content of nickel, cobalt and chromium

Morphophysiological characteristics and peculiarities of adrenal gland of bank vole (Clethrionomys glareolus) were studied in the area of natural biogeochemical province with abnormally high content of nickel, cobalt and chromium. The control population inhabited area with usual content of these elements. We used 4-factor analysis of variance to estimate the influence of geochemical conditions, phase of population cycle, sex and reproductive state on the morphophysiological characteristics of animals and functional activity of adrenal gland. Animals from area with high concentration of Ni, Co and Cr show an increase in relative mass of adrenal glands, fascicular zone of adrenal cortex, size of cells and their nuclei. All these changes can be considered as an evidence of increased secretion of glucocorticoids. It is shown that phase of population cycle influences fatness of animals, size of nuclei, cells and adrenal cortex. Females in comparison with males are characterized with higher indexes of liver and adrenal gland, as well as morphometric indexes of adrenal cortex. The maturation of animals is accompanied with increase in body mass, fatness and relative mass of adrenal glands, the size of cortex zone, nuclei and cells themselves. It is supposed that the effect of "geochemical factor" results in intensification of glucocorticoid secretion of adrenal costex, thus increasing non-specific resistance of animals inhabiting area with high concentration of heavy metals. Such factors as "phase of population cycle", "sex" and "reproductive state", influence mineralocorticoid activity, glucocorticoid and androgenic functions of adrenal cortex. Some factors show synergetic effect.     

Influence of age and artificial vaginal stimulation on fertility in female bank voles (Clethrionomys glareolus)

Female bank voles mated when 30-50 days old showed only 20-25% fertility at the first mating, but fertility increased to about 80% in animals greater than 100 days of age at the first mating. Young females subjected to artificial cervical stimulation after the completion of a normal mating showed a much higher fertility than normally mated controls (76 compared with 29%). The reason for the low fertility therefore appears to be that young females require more stimulation to activate the corpora lutea than is normally received at a mating.     

Maturity, castration and behaviour of male Bank voles, Clethrionomys glareolus (Mammalia)

This paper discusses the relationship between aggressive behaviour and sexual maturity, prepubertal castration and wounding in male Bank voles, Clethrionomys glareolus. In neutral arena tests in the laboratory, sexually mature males exhibited more aggressive components of behaviour than immature males or than adult males that had been castrated prepubertally. Mature males also exhibited fewer amicable components than the immature or castrated males. During several months residence in large outdoor enclosures, mature males consistently had more fresh skin wounds (inflicted by other voles) than did either immature or castrated males. The relevance of these results to the population ecology of Bank voles is discussed.     

Seasonal effects on sexual maturation of male bank voles (Clethrionomys glareolus)

The weights of the testes and accessory glands, and the degree of morphological and functional development of the seminiferous tubules, were used as indicators of sexual maturation in male bank voles. Males reared under constant laboratory conditions showed a significant relationship between the seasons and sexual maturation. Young males reached maturity most rapidly in the reproduction season (mid-April to mid-October), while adult males matured earlier, in the spring season (mid-January to mid-April). The influence of season on animals reared in outdoor cages was much more pronounced. One of the important factors was the photoperiod: animals reared from 3 to 12 weeks of age in a short photoperiod (8L:16D) matured less rapidly than did those reared in 16L:8D.     

Androgen-dependent proteins in the urine of bank voles (Clethrionomys glareolus)

The concentration of proteins in the urine of adult bank vole males was higher than that in urine of immature males and females. After separation of the urine by polyacrylamide gel electrophoresis in the presence of SDS, the principal urinary protein had a slightly lower mobility than cytochrome C. Urine from females or castrated males contained only trace amounts of this protein. Injection of testosterone into castrated males increased this protein band. We suggest that bank vole males, like those of rats and mice, synthesize and release in their urine an androgen-dependent protein fraction.     

The reproductive cycle of the Skomer vole (Clethrionomys glareolus skomerensis)

A histological examination has been made of the reproductive organs of the Skomer vole to study the reproductive cycle and fertility of this race of the Bank vole ( Clethrionomys glareolus ) in its insular habitat. The main aim of the work was to compare the cycle with that of Clethrionomys on the mainland of Britain which was similarly investigated by Brambell & Rowlands (1936).     

Effects of diet on reproductive performance of the Bank vole (Clethrionomys glareolus)

Laboratory experiments were carried out to test the effect of dietary supplements of fresh sprouted wheat on reproduction of the Bank vole, Clethrionomys glareolus. One hundred and twenty females were divided into three groups at weaning: (a) group NSS (no sprout supplement), (b) group LSS (low sprout supplement) and (c) group HSS (high sprout supplement). Six- to seven-week-old females were paired with fertile males. Both groups on sprout supplement showed a significantly higher incidence of pregnancy in primiparous females (76%) compared with controls (NSS) (46%). Diet had no significant effect on the incidence of pregnancy in multiparous females. Control females had consistently higher mean litter sizes up to and including the fifth litter, compared with experimental females. Primiparous NSS females had the highest mean litter size and the experimental group HSS had the lowest. Differences in mean litter interval between groups were related to litter size (number of sucklings) rather than diet. The number of foetuses in utero had no effect on litter interval. The incidence of post-partum conception was higher in group LSS as compared with groups HSS and NSS. Diet did not affect the mean number of young produced per female in a given time, or the percentage of young surviving to weaning. The results are discussed with reference to their implications regarding habitat suitability of C. glareolus.     

Highly polymorphic microsatellite loci in the bank vole (Clethrionomys glareolus)

We describe seven polymorphic, dinucleotide microsatellite loci isolated from bank voles (Clethrionomys glareolus, Rodentia: Muridae) collected from the Wirral Peninsula, United Kingdom. Microsatellites were isolated as part of a long‐term study on the wider effects of host–pathogen interactions of an endemic viral disease. These microsatellites showed between five and 13 alleles per locus in these populations. Observed and expected heterozygosities varied between 0.275 to 0.777 and 0.487 to 0.794, respectively. These markers will allow us to investigate the structure of this bank vole population.