Genetic Distinctiveness of the Korean Red-Backed Vole (Myodes regulus) from Korea, Revealed by Mitochondrial Cytochrome b Gene Sequences

To examine the taxonomic status of the Korean red-backed vole (Myodes regulus), the full cytochrome b sequences of 21 red-backed voles from Korea and northeast China were compared with the corresponding haplotypes from 12 species of Myodes and Eothenomys from GenBank. We identified five red-backed voles from Mount Changbai and Harbin as Myodes rufocanus and three from Harbin as M. rutilus, and we confirmed that the red-backed voles from Korea are M. regulus and not Eothenomys regulus. We found that M. regulus from Korea differed from the other five species of Myodes and that the interspecific distances between M. regulus and each of the two species from northeast China were 4.55% (M. rufocanus) and 11.1% (M. rutilus). We concluded that M. regulus is also genetically distinct and is an endemic species of Korea.     

绒鼠类系统学研究(啮齿目:仓鼠科:田鼠亚科)

在系统综述的基础上对绒鼠属Eothenomys的分类进行了探讨,认为Eothenomys属的典型特征应力;下颌骨臼齿咀嚼面左右两侧的三角形齿环均不呈交错排列,而是两两相对,彼此相融合;二倍染色体数2m=56,全部常染色体均为端部着丝粒（T）,东方绒鼠亚属Antheliomys5种中,至少玉龙绒鼠E.proditor不属于此属不能排除恢复Antheliomys属级分类地位的可能性,同意将Caryomys独立为绒Ping属;将Craseomys shanseius Thomas,1908(=E.shanseius)订正为棕背Ping的山西亚种C.r.shanseius。台湾绒鼠Eothenomys kanoi Tokuda,1937的染色体特征与Clethrionomys属相似,不应收入绒鼠属,其分类地位待定。Clethrionomys属和Eothenomys属化石种均最早出现于早更新世,目前还不能断定此二属究竟谁起源于谁,也许它们共同起源于第三者。     

Gene-geographical variation and genetic differentiation in red-backed voles of the genus Clethrionomys (Rodentia,Cricetidae) in the Okhotskii region

Thirteen enzyme systems and three nonenzyme proteins were electrophoretically analyzed in red-backed voles of the genus Clethrionomys. In total, 25 loci were interpreted. Gene-geographic variation was studied and indices of genetic variability and differentiation were determined. By the distribution of electrophoretic variants of hemoglobin, C. rutilus was shown to be divided into two geographical groups (northern and southern). A low level of genetic differentiation was revealed in the island isolates of C. rutilus and C. rufocanus. Separation of C. rufocanus, C. rex, and C. sicotanensis into a superspecies complex was confirmed. A study of differential G- and C-banding on C. rutilus and C. rufocanus chromosomes did not reveal intraspecific variation of autosomes. In these species, karyotypes of voles from Kamchatka Peninsula were studied for the first time. They appeared to be morphologically similar to the karyotypes continental voles by both autosomes and sex chromosomes.     

The factors influencing the sound activity of forest voles]

The article is devoted to the effect of context on the acoustic activity of bank voles of 4 species (Clethrionomys glareolus, C. centralis, C. rutilus, and C. rufocanus) living in experimental groups. In addition to species differences and social state of a specimen in the group, the acoustic activities of vole is affected by such factors as locomotor activity of the vole itself and its partners (especially dominant ones) and aggression of surrounding voles.     

Patterns of coexistence: ectoparasites on small mammals in northern Fennoscandia

The total aestival ectoparasitic burden of six small mammal species ( Sorex araneus, Clethrionomys glareolus, C. rutilus, C. rufocanus, Microtus agrestis , and M. oeconomus ) was investigated in terms of frequency distribution, frequency of occurrence, species diversity and joint occurrences. The mammals were collected in northern Fennoscandia during peak density years. The frequency distribution of the ectoparasites was best described as negative binomial on C. glareolus, M. agrestis , and M. oeconomus but not so on S. araneus, C. rutilus and C. rufocanus. The distribution did not fit the Poisson distribution in any species. The percentage of S. araneus that had ectoparasites was 49%, and of the microtidae species, 73-96% had ectoparasites. The median number of ectoparasites on the vole species was between 2 and 9 specimens of 1 or 2 species. There was a significant, positive correlation between the number of ectoparasitic species and the total number of individuals on all host species. Pairs of ectoparasitic species occurring together more or less often than expected by chance were found on all host species. However, the pairs rarely repeated themselves on the same host species under different environmental conditions, or on other host species under similar circumstances. Differences in total infestation between reproductive categories and sexes were observed in M. agrestis but not in S. araneus and C. glareolus.     

Molecular phylogeny and biogeography of Oriental voles: genus Eothenomys (Muridae, Mammalia)

Oriental voles of the genus Eothenomys are predominantly distributed along the Southeastern shoulder of the Qinghai-Tibetan Plateau. Based on phylogenetic analyses of the mitochondrial cytochrome b gene (1143 bp) obtained from 23 specimens (eight species) of Oriental voles collected from this area, together with nucleotide sequences from six specimens (two species) of Japanese red-backed voles (Eothenomys andersoni and Eothenomys smithii) and five species of the closely related genus Clethrionomys, we revised the systematic status of Eothenomys. We also tested if vicariance could explain the observed high species diversity in this area by correlating estimated divergence times to species distribution patterns and corresponding paleo-geographic events. Our results suggest that: (1) the eight species of Oriental voles form a monophyletic group with two distinct clades, and that these two clades should be considered as valid subgenera--Eothenomys and Anteliomys; (2) Eothenomys eleusis and Eothenomys miletus are not independent species; (3) Japanese red-backed voles are more closely related to the genus Clethrionomys than to continental Asian Eothenomys taxa; and (4) the genus Clethrionomys, as presently defined, is paraphyletic. In addition, the process of speciation of Oriental voles appears to be related to the Trans-Himalayan formation via three recent uplift events of the Qinghai-Tibetan Plateau within the last 3.6 million years, as well as to the effects of the mid-Quaternary ice age.     

中国森林田鼠族系统分类研究进展(啮齿目:仓鼠科:䶄亚科)

森林田鼠族（Myodini）是䶄亚科（Arvicolinae）的重要类群,广泛分布于整个全北区及东洋区部分区域,该族目前存在的分类学问题是缺乏化石标本、短时间的物种分化、有限分子样本和部分类群采样困难等综合因素影响的结果。近年中国森林田鼠族的系统分类研究成果主要有：（1）绒鼠属（Eothenomys）的采样和系统发育研究基本涵盖了全部类群,发现1新亚属和4新种,分别为川西绒鼠亚属（Ermites）和石棉绒鼠（Eothenomys shimianensis）、金阳绒鼠（E.jinyangensis）、美姑绒鼠（E.meiguensis）、螺髻山绒鼠（E.luojishanensis）,原来被普遍接受的黑腹绒鼠福建亚种（E.melanogaster colurnus）、中华绒鼠康定亚种（E.chinensis tarquinius）、西南绒鼠康定亚种（E.custos hintoni）被证实为3个独立有效种,滇绒鼠（E.eleusis）、丽江绒鼠（E.fidelis）的种级分类地位进一步得到确认;大绒鼠贡山亚种（E.miletus confinii）和黑腹绒鼠滇西亚种（E.melanogaster libonotus）实为克钦绒鼠（E.cachinus）的同物异名。（2）基于形态和分子系统发育的研究支持恢复东亚䶄属（Craseomys）的属级分类地位,同时解决了䶄属（Myodes）的非单系起源问题;研究进一步证实山西䶄（Craseomys shanseius）应为棕背䶄的山西亚种（Craseomys rufocanus shanseius）。（3）高山䶄属（Alticola）的平颅高山䶄亚属（Platycranius）分类地位受到分子系统发育研究结果质疑,该亚属的唯一物种平颅高山䶄（Alticola strelzowi）与高山䶄属指名亚属物种聚在同一枝;库蒙高山䶄（A.stracheyi）实为斯氏高山䶄（A.stoliczkanus）的同物异名。基于近年系统分类研究结果,目前中国森林田鼠族分布有5属共30种。     

Effects of age and seasonal rhythm on the growth patterns of some small mammals in Finland and in Kirkenes, Norway

The intensity of growth of Sorex araneus L. and Clethrionomys glareolus Schreb. in the Oulu district of Finland is studied as a function of age and seasonal rhythm, and compared with the results of growth-rate measurements of Sorex araneus L., Clethrionomys rufocanus Sund. and Clethrionomys rutilus Pall. in Kirkenes, Norway. It is assumed that the postnatal development of the Common shrew with its growth and regression phases is to some extent controlled by an endogenous seasonal rhythm. The growth of the voles is not as clearly controlled by these rhythms as that of the Common shrew although the growth of the Bank vole and Northern red-backed vole is obviously considerably retarded in autumn and in winter.     

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...     

Intra- and interspecific nuclear ribosomal gene variation in the two Japanese Eothenomys species, E. andersoni and E. smithii

We analyzed partial sequences (approx. 630 bp) of the 18S nuclear ribosomal RNA gene (rDNA) in the Japanese Eothenomys voles, E. andersoni and E. smithii, to evaluate their evolutionary complexity. There were two rDNA types of sequences with a few substitutions and an indel, and both species alternatively carried one of the two rDNA types, irrespective of their classifications. One of the rDNA types was mainly distributed in Eastern Japan, and the other in Western Japan. Such rDNA type distributions were not related to the species classifications. The complex genomic elements across both species were confirmed by previous studies of nuclear, mitochondrial, and Y chromosomal genes, and our current data agree with previous findings. Previous studies indicated that the genome constitutions of the Japanese Eothenomys species may have been caused by interspecific genetic exchanges at an early period after the speciation into E. andersoni and E. smithii from their common ancestor, as neither species crosses at present. In addition, the present results also suggest the additional hypothesis that their common ancestor might have two (or more) rDNA gene types, and that one of the rDNA types was fixed in each population of both species during their colonization processes.     

Life histories of Clethrionomys and Microtus (Microtinae)

Although there have been numerous life-history reviews of mammals at high taxonomic levels (e.g. among families within orders), there are far fewer studies at lower taxonomic levels (e.g. among species within genera). Data on adult weights, litter size, gestation length, neonate weight, age and weight at weaning, growth rate to weaning, maximum life span, and length of the breeding season were compiled from the literature on five species of Clethrionomys and 33 species of Microtus. Variability in litter size and male body weights was not significantly different when compared between cyclic and non-cyclic populations. Coefficients of variation were also calculated for the three species with the most data (C. gapperi, C. glareolus and M. pennsylvanicus ). These values showed that the amount of intraspecific variation differed among traits as well as among species. Gestation length was the most invariable of all traits and variation in adult weights, neonate weight, gestation length, and litter size had similar values to those reported for Peromyscus maniculatus. Five and eight traits differed among Clethrionomys and Microtus species, respectively. Differences in litter size, adult weights and length of the breeding season were common to both genera. Male weight, gestation length and neonate weight as well as length of the breeding season were different between genera. Very few traits covaried within C. gapperi, C. glareolus or M. pennsylvanicus. Similarly, few traits covaried among all Clethrionomys populations. However, among all Microtus populations and Microtus species, 11 and 12 correlations were significant. Many of the patterns found in Microtus involved positive relationships between female weight and some other trait. These patterns have also been found by broader surveys at higher taxonomic levels. Large species of Microtus had larger offspring, a greater litter size and occurred in short-season environments relative to small species of this genus.     

Intra- and interspecific genetic complexities of two Eothenomys species in Honshu, Japan

Differences in the nuclear ribosomal DNA (rDNA), mitochondrial DNA (mtDNA), cytochrome b (Cytb), and Y chromosomal Sry genes were used to assess intra- and interspecific relationships in two Japanese red-backed voles, Eothenomys andersoni and E. smithii, focusing on areas where the two species might come into contact. In the Kii Peninsula, southwestern Honshu, which contains an allopatric population of E. andersoni isolated from its main range, the rDNA-RFLP data provide robust evidence of past mutual interspecific gene introgression, while the Cytb and Sry sequences were specific to this population. In central Honshu, where E. andersoni and E. smithii inhabit higher and lower altitudes, respectively, with a narrow sympatric zone, the rDNA-RFLP and Sry variation was specific for each species, while introgression of the mtDNA from E. smithii to E. andersoni was seen. These complex patterns in the gene markers are consistent with our previous notions derived from sex chromosome variation. Our previous and present data strongly suggest that the evolution of these vole species, which are morphologically and cytogenetically distinct, involves complex genetic interactions and the resultant combinations of genes are sometimes peculiar, mainly due to the Cytb haplotypes. However, phylogenetic analysis using a combination of maternal, paternal, and biparental markers has proven useful for understanding the evolutionary history given the complex phylogenetic background.     

Functional motor asymmetry in three species of mouse rodents from natural populations

Motor asymmetry of paws was studied in three species of mouse rodents (Apodemus agrarius, Clethrionomys glareolus, Clethrionomys rutilus) from natural populations. The prevalence of right-hand asymmetry was revealed in both males and females of all studied species. The spatial and temporal variability of asymmetry structures was shown. The increased number of left-handed rodents was observed in unfavorable habitats. A possible adaptive role of the functional motor asymmetry exemplified by small rodents is discussed.     

阿拉斯加东南部温带雨林加氏(鼠平)和肯氏鹿鼠密度与微生境利用的相关性

为了验证对阿拉斯加东南部温带雨林中有关栖息地关系的预测,我们于1999年和2000年8-9月以及1999年和2000年4-5月研究了亚历山大群岛加氏(Clethrionomys gapperi)和肯氏鹿鼠(Peromyscus keeni)种群。我们测量了26个植被和结构特征以检验林隙老龄生长林、多时代老龄生长林、采伐前壮龄(23岁)生长林和泥炭混交针叶林的丰富度与微栖息地利用的相关性。微栖息地利用随季节和栖息地而变化,但加氏与林下落叶灌木覆盖度的正相关最显著。肯氏鹿鼠利用的微环境的林地有较少的苔藓,但是林隙与抓获加氏的概率有直接关系。两种鼠在两个季节的密度与林下腐朽的倒木直接相关。春季的肯氏鹿鼠密度说明加氏密度变化的62%,说明肯氏鹿鼠密度变化的89%。我们的结果印证了早期对阿拉斯加东南部肯氏鹿鼠在各种栖息地尤其早期的演替林中兴旺时的研究;但偏离了西部地貌中肯氏鹿鼠种群在晚期演替针叶林中达到最高密度的普遍结论。与北美西北部其它地区的种群不同,加氏能持久生活在上层被砍伐的雨林板块中。泥炭针叶混交林对两种鼠的繁殖种群几乎没有贡献,因而不可能减轻对多产的老龄生长雨林大规模皆伐所造成的影响。     

紫貂冬季食性的分析

１９９１至１９９８年的三个冬季,在大兴安岭地区共收集紫貂粪样２２３个．食性分析结果表明,紫貂冬季食物主要为小型哺乳类（５４．１％）、植物浆果和种子（３２．４％）、鸟类（１２．５％）和昆虫（１．０％）．在紫貂选择的７种小型哺乳类中,主要以棕背（２７．３％）和红背（１９．２％）为食,其次为雪兔和冬眠的花鼠。对于鸟类,紫貂主要捕食花尾榛鸡（８．１％）,松鸦（０．７％）,大山雀（０．５％）和黑啄本鸟等。有２．２％的粪样中含有小型鸟的卵壳、紫貂的植物性食物主要为越桔浆果（２０．８％）和偃松种籽（８．８％）。昆虫中只有蚂蚁在紫貂食性中出现（１．０％）．紫貂冬季食物构成没有年度间差异（Ｐ＞０．０５）。通过捕食迹,我们还发现紫貂捕食黑嘴松鸡。虽然红背的捕获率（７９．４％）高于棕背（２．９％）,但食性分析结果却相反,说明紫貂更喜欢捕捉身体较大的鼠类。有较强气味的中虽有一定的数量,但在紫貂冬季食物中未出现过。     

Reproductive compatibility of voles from separate continents (Mammalia: Clethrionomys

The North American Red-backed vole, Clethrionomys gapperi , and the Eurasian Bank vole, C. glareolus , are probably derived from a common ancestor. They have been isolated from each other for a minimum of 20,000 generations, probably many more. Interbreeding experiments in the laboratory show that in that time only partial reproductive isolation has developed. They interbreed as frequently as do pure strain pairs, and produce litters of approximately the same size. Hybrids exhibit reduced viability, but this may be partly an artifact produced by the laboratory rearing conditions. If they ever made contact in nature the most likely outcome appears to be selection against hybrids leading to full speciation and the establishment of contiguous allopatry. It is recommended that they be considered semispecies, in the terminology of Mayr (1963), and retain their separate names.     

Spatio-temporal interrelations of three sympatric species of voles (Mammalia: Rodentia) in the South Urals

The structural and functional organization and the spatio-temporal interrelations of three sympatric vole species (Microtus oeconomus, Clethrionomys, rutilus, and C. rufocanus) were analyzed on territories different in the type of their functional significance to the animals (survival stations, zones of temporary dispersal, and transit zones). The study was conducted in the environs of the Iremel massif (54 degrees 31'25" N 58 degrees 50'18" E) in 1979-1981, in four 1 ha marking-areas in four different altitudinal zones. It is shown that the abundance and demographic structure is different for each species pair in each area, whereas their dynamics in synchronous. The overlap of niches in two Clethrionomys species is small and cannot cause their competition for food. The distribution of voles within the areas is usually independent, but has some peculiarities depending on the type of territory usage by the animals. Preferred microterritories that help species to avoid competition are revealed for each species to occur in different areas. These are cases of spatial separation, not of ecological isolation of sympatric species. Spatial and temporal division of environmental resources is controlled by mechanisms that have developed in the process of the community's evolution.     

Seasonal changes in the energy metabolism of subarctic rodents

In widespread species, northern taiga voles, most significant differences in the intensity of energy metabolism (M), maximum (Mmax) and reserve (Mres) metabolism were observed at winter temperatures (-5-20 degrees C): Clethrionomys rutilus greater than C. rufocanus greater than Microtus oeconomus; differences in seasonal increase of Mmax and Mres exhibit an inverse proportion. Seasonal changes in M and Mmax in autochthonous tundra rodents indicate that Lemmus sibiricus belongs to a more eurybiont species as compared to Dicrostonyx torquatus. The main characteristic feature of seasonal adaptation of M in lemmings, as compared to voles, is the evident decrease of M value in winter which is accompanied by a more significant increase of Mmax and Mres. Operative pattern and high seasonal mobility of chemical thermoregulation in lemmings are suggested which account for adaptation of these animals mainly to short-term extreme effects of low temperatures.     

五种啮齿类动物核型和血清蛋白质的SDS-聚丙烯酰胺凝胶电泳分析

本文对5种啮齿类动物(岩松鼠、花鼠、五趾跳鼠、棕背(鼠平)和岢岚绒鼠)的核型及其血清蛋白质的SDS-聚丙烯酰胺凝胶电泳进行了分析。通过分析结果,探讨了它们的核型及血清蛋白在其分类中的意义。     

Delayed maturation in female bank voles: optimal decision or social constraint?

1. Density, maturation and survival of female bank vole ( Clethrionomys glareolus ) in the northern taiga of Finnish Lapland were studied using long-term capture–mark–recapture data from two large grids, one food-addition grid and one control grid, in 1982–94.
2. The density on the food grid was consistently higher than the density on the control grid.
3. Females born early in the breeding season usually matured, except at very high densities. Those born later in the summer season commonly delayed maturation to the following spring.
4. Winter survival of sub-adult (having delayed maturation) females was significantly higher than survival of adult (breeding) females. However, empirical values of sub-adult and adult survival, as well as difference between them, were not consistent with survival values assumed in theoretical models on optimal deferred breeding.
5. There was a density-dependent relationship between the maturation rate of young voles and the density of already established breeding females (both bank voles and all Clethrionomys together; C. rutilus and C. rufocanus occasionally occurred on the study grids). This density dependence was different for the two grids (weaker on the food-addition grid).
6. These findings are discussed within an evolutionary context: we have, on the basis of these findings, no evidence suggesting that the observed delayed maturation represents an evolutionary optimal strategy. Rather, there is evidence suggesting that the delay is due to social constraints.