Bank Vole Myodes Glareolus Schreber Research Articles

Vegetation cover and microtine rodents spatial distribution under conditions of Nizhny Novgorod oakwood

This paper deals with the problem of the connection between small mammals spatial distribution and the vegetation cover. The study was carried out during the summer period of 2018 and 2019 in the landscape protected area Oakwood of the NNSU Botanical Garden in the province of Nizhny Novgorod. Three relevs were set up in various plant associations: Ulmetum pulmonarioso-asaroso-aegopodiosum, Acereto-Tilietum pulmonarioso-impatienosum (noli-tangerae), Querceto-Acereto-Tilietum asareto-aegopodiosum. A standard geobotanical description was carried out according to the generally accepted method using a series of Raunkier sites registration. Microtine rodents were trapped by standart traps and live traps. The caught animals turned out to belong to 2 genera and 3 species: the bank vole Myodes glareolus Schreber, the pygmy wood mouse Apodemus uralensis Pallas, and the field mouse Apodemus agrarius Pallas. The low population size of animals, as well as the fact that Apodemus agrarius is a co-dominant, may indirectly indicate the anthropogenic pressure in the investigated oak groves. Ecological plasticity of the species Myodes glareolus has been confirmed. Bank voles inhabit micro-habitats with the average data of illumination as well as shaded ones. In general, the vegetation projective cover and the presence of Norway maple undergrowth are crucial for the microtine rodents spatial distribution. Small mammals choose sites with a minimum number of Acer platanoides undergrowth, and gravitate to places where the projective cover of grass has moderate rates (from 35 to 50%). The Principal Component Analysis (PCA) using a vegetation cover species spectrum showed the presence of a significant factor for microtine rodents, which is associated with nitrophilous species (common nettle and touch-me-not balsam). The presence of those plants may indicate a significant anthropogenic pressure on the vegetation cover. In addition, it is important that plants belong to a particular eco-coenotic group. The species Myodes glareolus and Apodemus agrarius differ on the nemoral factor, and their ecological niches do not overlap.

Experimental Investigation of Interrelations between Small Rodents and Red Wood Ants

Investigations of the mechanisms of the spatial-behavioral interaction of members of diverse and significant guilds such as red wood ants and small mammals have been started only recently, and many questions remain obscure. We have investigated interrelations between red wood ants Formica aquilonia Yarr and the common vole Microtus arvalis Pallas, the bank vole Myodes glareolus Schreber, and the pygmy wood mouse Sylvaemus uralensis Pallas in laboratory experiments. We first describe the defensive behavior of rodents and reveal a stereotype of the hunting behavior of the common vole towards dangerous insects. In all three rodent species, defensive behavior increases with an increase in the number of ants used in the tests, which corresponds to simulated natural situations with gradations of the dynamic density of insects. We speculate about the relationship between the defensive and hunting behavior of rodents towards red wood ants.

Copulatory behaviour of the bank voleMyodes glareolus: matings with one and two males do not make a difference

In promiscuous species in which females mate with more than one male during oestrus, males may increase their sperm expenditure or change their copulatory behaviour in response to the risk of sperm competition. I used an experimental approach to investigate the pattern of copulatory behaviour of the bank voleMyodes glareolus Schreber, 1780 depending on whether the female mated with one or two males. The work showed that the copulatory period of the bank vole lasted about 80 minutes and consisted of 4–5 ejaculatory series, with multiple intromissions preceding ejaculation. There were no significant changes in number of intromissions across the first four ejaculatory series, but I did find a relationship between number of intromissions and first ejaculation latency; also, ejaculation latencies grew shorter as the ejaculatory series proceeded. Litter size did not differ significantly between females that mated with one male and those mating with two, nor did the reproductive success of males that mated with the same female. Mating with an oestrus female appears to be advantageous for bank vole males even if they mate as the second one, and the risk of sperm competition did not trigger changes in male copulatory behaviour. The similar durations of the copulatory period and patterns of change of ejaculation latencies during copulations with one and two males point to the role of the female in temporal copulatory behaviour of the bank vole.

Habitat preferences of the bank voleMyodes glareolus in a Mediterranean mountain range

The bank voleMyodes glareolus Schreber, 1780 is a widely distributed rodent in Europe, being numerically dominant in small mammal communities living in temperate woodlands. However, it becomes scarce in southern Europe (Mediterranean area) where it reaches the southernmost limit of its distribution range. We studied the habitat preferences of bank voles in 9 plots in a transitional area between Mediterranean and Eurosiberian regions within a Mediterranean mountain. During the study period we captured 1919 small mammals of 9 species, including 287 bank voles (14.95%). Mean density ranged from zero individuals per plot (1.1 ha) at the boreo-subalpine scrubland to 10.27 ± 2.84 (SE) at a Mediterranean river woodland. Statistical path analysis was used to investigate relationships between mean bank vole density and climate and vegetation structure measured within plots. The variables selected by the structural equation model were those related to forest structure, like tree cover and height, dead vegetation, moss, and rock cover. Habitat moisture was also important (microclimatic conditions). Mean climate conditions (and elevation) did not have any significant effect on mean bank vole density, and no significant association with understorey vegetation (eg shrub and herbaceous cover) was observed. Our results pointed out that bank voles were habitat specialists in our study area, being more abundant and frequent in moist woodlands, and rare or absent in shrublands and grasslands.

Density-dependent variation in body mass of voles

We studied inter-annual, spatial and sexual variation in the body mass of bank volesMyodes glareolus Schreber, 1780 and grey-sided volesMyodes rufocanus Sundevall, 1846 using live trappings from two grids on the southand north-facing slopes of a mountain valley in Southern Norway. Variation in spring density of the four populations was consistent with cyclic dynamics (n=7,s-values >0.5). Individuals caught on the south-facing slope were larger than those caught on the north-facing slope. Reproductively mature bank vole males were smaller than females, whereas reproductively mature grey-sided vole males were larger than females. Body mass was related to density in both species. In bank voles, we found a direct positive density dependence caused by a higher rate of survival at higher densities resulting from individual allocation of resources from reproduction to survival and growth. In grey-sided voles, we found a negative delayed density dependence resulting from grazing on preferred plants that determined the resource available for individual vole growth the following year.

Density-dependent regulatory mechanisms of the generative potency in the males of a bank voleMyodes glareolus

Morphological analysis revealed destructive changes in the testicular tissue of bank volesMyodes glareolus Schreber, 1780 during different phases of a population fluctuation. The most pronounced changes were observed at the peak phase, when karyolysis of the Leydig cells and degeneration of spermatogenous cells were recorded in 90% of males. During the increase phase, depression of androgenous testicular function was observed in only 50% of males and atrophy of seminiferous tubules in 30% of males. During the low phase, the proportion of males with destructive changes in generative and endocrine portions of the testicles did not exceed 30%. Morphometrical analysis of spermatozoa demonstrated that the size of the head and nucleus were related to the phase of the population fluctuation. Lengths of the middle and main parts of the spermatozoon tail, as well as the size of the acrosome, were not related to phase of the population fluctuation.