鼹形田鼠入侵鼠和留居鼠之间的相互作用

我们研究了营掘地生活的社会性啮齿类——鼹形田鼠(Ellobius talpinus Pall．)对陌生鼠入侵完整家庭所占据洞穴系统后的行为和内分泌反应。在繁殖期和非繁殖期,所有的入侵鼠都在进入洞穴2天内从留居鼠的洞穴系统内消失;而在引入空洞穴的7只鼹形田鼠中,有4只至少在该洞穴中停留了2天。引入陌生鼠导致留居鼠在释放地的集中,并引起留居鼠和入侵鼠血浆中皮质酮水平的增加。在繁殖期,在引入陌生鼠的当天,也伴随着留居鼠血浆中睾酮增加的现象。所以,对陌生鼠入侵的模拟表明了留居鼹形田鼠有效的社会性防范,这可能是该物种家庭大小和结构稳定的一个重要机制。留居鼠和入侵鼠的相遇激活了压力的生理机制,特别是在繁殖季节更是如此[动物学报50(1)：19-26,2004]。     

Inheritance of coat color in the mole vole (Ellobius talpinus Pallas)

Based on the ecological features of the mole vole, family analysis of the inheritance of coat color was performed with the use of material collected in a wild population. Analysis of coat color in parents and offspring has demonstrated that the offspring segregation into black and nonblack animals after crosses of different types agrees with the hypothesis on the monogenic inheritance of these color variations. Black mole voles are homozygous for the recessive allele (genotype aa). Homozygotes for the dominant allele (AA) are brown. Heterozygotes (Aa) may be brown or have transitional color. The mean frequency of brown coat color in heterozygotes is 0.509 and is very variable. The higher the color intensity in black elements of parent coat color, the more is the offspring coat color saturated with these elements.     

Structure of colonies in the northern mole vole, Ellobius talpinus (Rodentia, Cricetidae)

The structure of two northern mole vole colonies from northern Chelyabinsk oblast (the Kunashak colony, 1981–1983) and southern Kurgan oblast (the Kurtamysh colony, 1985–1999) has been analyzed with respect to the number and composition of families, seasonal and annual population dynamics, age and sex composition and sex ratio, individual life span, migrations, breeding, and reproductive potential. The Kunashak colony is at the northwestern boundary of the species range, and its population is monomorphic (all animals are of the black color morph). The Kurtamysh colony is located in an optimal habitat, and its population is polymorphic, consisting of animals of three color morphs (black, brown, and transitional). Consideration is given to certain specific features of northern mole voles belonging to different color morphs.     

A comparative analysis of the mole vole sibling species Ellobius tancrei and E. talpinus (Cricetidae, Rodentia) through chromosome painting and examination of synaptonemal complex structures in hybrids

A comparative genomic analysis was carried out in the mole vole sibling species Ellobius tancrei and E. talpinus. Performing fluorescent in situ hybridisation (Zoo-FISH) using chromosome paints from the field vole Microtus agrestis showed no differences in the allocation of syntenic groups in the karyotypes of these sibling species. The only difference between their karyotypes was the position of the centromere in one pair of chromosomes, which is assumed to be the result of an inversion. To verify this hypothesis, we analysed chromosome synapsis in prophase I of meiosis. We utilised a synaptonemal complex (SC) surface-spreading technique to visualise the process of chromosome synapsis in the spermatocytes and oocytes of first-generation hybrids and back-crosses of these sibling species. In prophase I of meiosis, immunocytochemical and electron microscopy analyses revealed that all bivalents had been fully adjusted. Even in the case of a submetacentric-acrocentric bivalent with different centromere locations, synapsis of SC lateral elements was fulfilled along the entire length of the chromosomes and the formation of an inversion loop was not observed. We hypothesise that a possible mechanism leading to the change in centromere position is the repositioning and/or generation of a neocentromere. Despite the great similarity in the karyotypes of these sibling species, they exhibited significant genomic diversification, which manifested as hybrid sterility and parous female death.     

Synaptonemal complexes and chromosome chains in the rodent Ellobius talpinus heterozygous for ten Robertsonian translocations

Synaptonemal complexes (SC) in four Ellobius talpinus males heterozygous for ten Robertsonian translocations were examined with an electron microscope using a surface-spreading technique. A total of 136 late zygotene and pachytene spermatocytes were examined. From one to three completely paired SC trivalents were found in each early pachytene spermatocyte. The lateral elements of the short arms of the acrocentric chromosomes in these trivalents were joined with an SC thus forming the third arm of the SC trivalent. At the same stage a few SC trivalents did not contain lateral elements in the pericentromeric region of the metacentric chromosomes and remained unpaired in this region up to mid pachytene. At zygotene and pachytene from two to eight SC trivalents were joined into chains due to formation of SCs between the short arms of acrocentrics of other SC trivalents. These chains are frequent at late zygotene, but are resolved during pachytene into individual trivalents. It is proposed that pairing and SC formation between the short arms of the acrocentric chromosomes results from the monosomy of the short arms and partial DNA homology between these heterochromatic regions. Since crossing over probably does not take place in these segments, the chromosomal chains may subsequently be corrected into trivalents by a dissolution of the SCs combining adjacent trivalents. The correction and disjoining of chains may not be effective in all cells. The cells in which the chains are retained are assumed to be arrested at the pachytene stage.     

Seasonal changes in the numerical responses of predators to cyclic vole populations

Theoretical models predict that a delayed density-dependent mortality factor with a time lag of ca 9 months is able to drive 3–5-yr population cycles of northern voles. We studied numerical responses of predators in western Finland during 1986–92, in an area with 3-yr population cycles of voles. Abundances of small mammals were monitored in several farmland areas (each 3 km²) by snap-trapping in April, June, August, and October (only in 1986–90), and the abundances of avian, mammalian, and reptilian predators by visual censuses during trapping occasions. The 3-yr cycle studied was a cycle of Microtus voles (field vole M. agrestis and sibling vole M. rossiaemeridionalis ) and their small-sized predators (small mustelids and vole-eating birds of prey). The numerical responses of both migratory avian predators and small mustelids to changes in vole densities were more alike than different. In late summer (August), the time lag in the numerical response of all main predators was short (0–4 months), whereas longer time lags prevailed from spring to early summer. The length of the time lag in spring appeared to be related to the length of the winter, which indicates that strong seasonality may create longer time lags to the numerical response of predators at northern latitudes than at more southern latitudes. Our results suggest that, from spring to early summer, predation by migratory avian predators may act in concordance with mustelid predation to produce the long time lag necessary to drive the 3-yr cycle of voles, whereas almost direct density-dependent predation by all major predators in late summer may dampen spatial variation in prey densities.     

Nasal aerodynamics protects brain and lung from inhaled dust in subterranean diggers,Ellobius talpinus

Inhalation of air-dispersed sub-micrometre and nano-sized particles presents a risk factor for animal and human health. Here, we show that nasal aerodynamics plays a pivotal role in the protection of the subterranean mole vole Ellobius talpinus from an increased exposure to nano-aerosols. Quantitative simulation of particle flow has shown that their deposition on the total surface of the nasal cavity is higher in the mole vole than in a terrestrial rodent Mus musculus (mouse), but lower on the olfactory epithelium. In agreement with simulation results, we found a reduced accumulation of manganese in olfactory bulbs of mole voles in comparison with mice after the inhalation of nano-sized MnCl₂ aerosols. We ruled out the possibility that this reduction is owing to a lower transportation from epithelium to brain in the mole vole as intranasal instillations of MnCl₂ solution and hydrated nanoparticles of manganese oxide MnO · (H₂O)_x revealed similar uptake rates for both species. Together, we conclude that nasal geometry contributes to the protection of brain and lung from accumulation of air-dispersed particles in mole voles.     

Seasonal changes in thermoregulation of the raccoon dog (Nyctereutes procyonoides Gray 1834)

Oxygen consumption (ml X kg-0.75/min) in relation to ambient temperature (Ta) in the raccoon dog whelps at the ages of 7-9 weeks and 17-19 weeks is described by equations y = 32.9-0.69x and y = 26.2-0.49x, respectively. The corresponding equations to adults in summer and winter pelages are y = 19.6-0.46x and y = 14.5-0.32x, respectively. The cooling constant (min-1) of deceased raccoon dogs decreased exponentially with increasing body mass, while M-0.75 specific heat transfer coefficient (W X kg-0.75/degrees C) regressed linearly on body mass, y = 0.124-0.00066x. Cooling rate of deceased animals were more dependent on body mass than on pelage quality.     

Frugal strategy as a base of mole-vole (Ellobius talpinus: Rodentia) adaptations to the fossorial way of life

Interspecies comparison of rodents (Rodentia, Cricetidae) of different ecological specialization has revealed dramatic differences in the most essential physiological life history traits between social fossorial mole vole (Ellobius talpinus) and terrestrial rodents. dwarf hamsters (Phodopus) and voles (Clethrionomys). Mole voles have decreased standard and maximal metabolic rates, reduced ability to maintain constant body temperature. lower rates of growth and sexual maturation, lower reproductive output, declined immune and stress response. These life history traits, shaped by the unique peculiarities of the soil environment, provide effective resource re-allocation towards the costly burrowing activity. Spatial and temporal variability of ecological conditions inevitable for any species additionally participate in re-allocation of internal resources. In cold seasons of the year mole voles increase their metabolic activity and become homeothermic. In the north-eastern periphery of the species range, mole voles are fare more stressed and differ from the individuals inhabit the central part of the range with decreased longevity and increased reproductive output on the level of the entire population.     

麻雀及黄胸鹀化学体温调节的季节变化及其适应性研究

本项研究选择麻雀及黄胸鹀为对象。着童分析比较了麻雀(留鸟)与黄胸鹀(候鸟)在化学体温调节季节变化方面的差异及其适应意义。 试验材料取自北京近郊南苑附近。于春、夏、秋、冬各季分别测定了由5℃至35℃ 7种温度等级的耗氧值(温度间隔为5℃)及试验前后的体温变化。共测定2,760只次,其中麻雀2,084只次,黄胸鹀676。用密闭呼吸室及自动测氧装置测定耗氧值,并用热电偶与EKO指针式检流计联用测试体温。现将所获结