| [the disposition of natural foci of hemorrhagic fever with renal syndrome in different landscape areas of tyumen province]. | lungs of 3159 animals of the forest complex from 90 areas of 30 administrative districts of tyumen province were examined by enzyme immunoassays for antigen of hemorrhagic fever with renal syndrome (hfrs) during 5 years, 1985-1989. the antigen of hers virus was detected in the lungs of mammals of 8 species: clethrionomys glareolus and cl. rutilus, siberian and arctic lemmings (first findings in the world), m. oeconomus, field mouse, common and pygmy shrews. nearly all the findings refer to the s ... | 1992 | 1359712 |
| aberrant sex chromosome mechanisms in mammals. evolutionary aspects. | there are a number of mammalian species with complicated or unknown mechanisms for sex determination. the literature is reviewed with special reference to the origin and evolution of the sex chromosome mechanisms in three species of monotremes and in the following species of rodents: the creeping vole (microtus oregoni), the mole vole (ellobius lutescens), the amami spinous country rat (tokudaia osimensis), the wood lemming (myopus schisticolor), the varying lemming (dicrostonyx torquatus), sout ... | 1983 | 6444170 |
| [the topography of gomori positive neurosecretory elements of the hypothalamus of the lemmings dicrostonyx torquatus and lemmus sibiricus]. | under study was the structure of the hypothalamo-hypophyseal neurosecretory system in two species of lemmings of the wrangel island: the collared lemming, (dicrostonyx torquatus) and the ob lemming (lemmus sibiricus). inspite of the similarity in the general organization of this system in all rodents, certain species features were found in the topography of neurosecretory elements in the animals studied. in the ob lemming there is a great similarity in the structures of the neurosecretory system ... | 1976 | 1275710 |
| sex ratio evolution in lemmings. | in the varying lemming, dicrostonyx torquatus, numerous xy females occur due to the x-linked mutation x*. gileva (1987) has shown that there is also segregation distortion in males, with the segregation ratio for y sperm being about 0.56, which has a significant effect on the sex ratio and the frequency of xy females. a theoretical analysis shows that this degree of segregation distortion is expected to evolve in the dicrostonyx system under random mating, provided that reproductive compensation ... | 1988 | 3058648 |
| the hypothalamo-hypophysial system of the lemming, dicrostonyx torquatus pallas. iii. population aspects of neuroendocrine regulation. | the structure and ultrastructure of the following regions of the hypothalamo-hypophysial neurosecretory system (hhns) in the population cycle of lemming were studied: supraoptic (son), paraventricular (pvn) and arcuate nuclei (an), the median eminence (me) and posterior pituitary (pp). being compared to the state of endocrine glands and gonads, and the level of reproduction stress in the population cycle of the lemming described earlier, the obtained data revealed a certain regularity. first, at ... | 1989 | 2683448 |
| the hypothalamo-hypophysial system of the lemming dicrostonyx torquatus pallas. iv. influence of experimental animal cooling on the ultrastructure of the hypothalamo-posthypophysial neurosecretory system. | the reaction of the hypothalamo-hypophysial neurosecretory system (hhns) of lemmings to cold (+4 degrees c) was studied by the method of electron microscopy. the animals were kept in cages with nest, but with no wheel to allow running; in cages with a wheel, but with no nest; in cages with no nest and no wheel. no changes in the hhns reaction were revealed under cold stimulation, if the animals were not deprived of motor activity (running in a wheel), or could hide in a nest. in case of no nest ... | 1989 | 2683449 |
| [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 eurybion ... | 2006 | 2596207 |
| chromosomal speciation and folliculogenesis in the semisterile interspecific hybrids of the varying lemmings, genus dicrostonyx. | karyotypes of dicrostonyx torquatus torquatus and d. vinogradovi that are very similar phenotypically differ at least by 13-14 chromosomal rearrangements including centric and tandem fusions, fissions and paracentric inversion. in their male hybrid f1 spermatogenesis is arrested on early pre-meiotic stages, the female hybrids are semisterile. histological investigation of ovaries has demonstrated reduced number of follicles, higher percentage of atretic follicles and an acceleration of folliculo ... | 2006 | 7863719 |
| [the population aspects of thyroid development in the siberian (lemmus sibiricus) and arctic (dicrostonyx torquatus) lemmings of wrangel island]. | rate of thyroid gland development differ significantly on the stages of growth, highest value and recession of quantity in lemmus sibiricus fetuses. rate of embryogenic thyroid gland development in the highest value of population quantity reduces compared to that observed during the quantity growth. however, this reduction is displayed in smaller extent than in embryos of dicrostonyx torquatus of the same population cycle stage. in newborns organ achieves definitive structure in highest value, w ... | 1996 | 8768570 |
| [eimeria nordensheldi sp. n.--a new species of coccidia (eucoccidiida, eimeridae) from the arctic lemming (dicrostonyx torquatus vinogradovi)]. | while studying parasites of the lemmings dicrostonyx torquatus vinogradovi ognev, 1948 from the coast of wrangel island a new species eimeria nordensheldi was found out. its description, figure and differential diagnosis are given. | 2007 | 9304103 |
| inbreeding and sex ratio in two captive colonies of dicrostonyx torquatus pall., 1779: a reply to g.h. jarrell. | | 1998 | 9687238 |
| description and morphometric variability of paranoplocephala serrata n. sp. (cestoda: anoplocephalidae) in collared lemmings (dicrostonyx spp., arvicolinae) from arctic siberia and north america. | we describe paranoplocephala serrata n. sp. (cestoda, anoplocephalidae) from collared lemmings dicrostonyx torquatus and d. groenlandicus (arvicolinae, rodentia) in arctic siberia and north america. the new species was recorded from the yamal peninsula (type-locality), yana delta, kolyma delta, wrangel island, alaska and victoria island/kent peninsula (northwest territories). p. serrata n. sp. is characterised by a long, ribbon-like strobila, distinctly serrated segments, a small scolex, unilate ... | 2000 | 10768764 |
| heavy metal contamination in the taimyr peninsula, siberian arctic. | the taimyr peninsula is directly north of the world's largest heavy metal smelting complex (norilsk, russia). despite this proximity, there has been little research to examine the extent of contamination of the taimyr peninsula. we analyzed heavy metal concentrations in lichen (cetraria cucullata), moss (hylocomium splendens), soils, lake sediment, freshwater fish (salvelinus alpinus, lota lota and coregonus spp.) and collared lemming (dicrostonyx torquatus) from 13 sites between 30 and 300 km f ... | 2003 | 12493191 |
| [the b chromosome system in the varying lemming dicrostonyx torquatus pall., 1779 from natural and laboratory populations]. | in varying lemmings from seven natural populations (from bolzhezemel'skaya tundra to chukotka peninsula), the number of b chromosomes ranged from 0 to 15. in populations surveyed for several years, b chromosome frequencies were stable. two laboratory colonies (founded by dicrostonyx torquatus from the polar urals and d. t. chionopaes from yakutia) produced more than 3000 animals, of which 1699 were karyotyped. a small excess of b chromosomes in the progeny over that in their parents was observed ... | 2004 | 15648152 |
| differences in the reaction of collared lemmings dicrostonyx torquatus to changes in the photoperiod. | | 2016 | 18841812 |
| serial population extinctions in a small mammal indicate late pleistocene ecosystem instability. | the late pleistocene global extinction of many terrestrial mammal species has been a subject of intensive scientific study for over a century, yet the relative contributions of environmental changes and the global expansion of humans remain unresolved. a defining component of these extinctions is a bias toward large species, with the majority of small-mammal taxa apparently surviving into the present. here, we investigate the population-level history of a key tundra-specialist small mammal, the ... | 2012 | 23185018 |
| rapid karyotype evolution in lasiopodomys involved at least two autosome - sex chromosome translocations. | the generic status of lasiopodomys and its division into subgenera lasiopodomys (l. mandarinus, l. brandtii) and stenocranius (l. gregalis, l. raddei) are not generally accepted because of contradictions between the morphological and molecular data. to obtain cytogenetic evidence for the lasiopodomys genus and its subgenera and to test the autosome to sex chromosome translocation hypothesis of sex chromosome complex origin in l. mandarinus proposed previously, we hybridized chromosome painting p ... | 2016 | 27936177 |
| a male-biased natal sex-ratio in inbred collared lemmings, dicrostonyx groenlandicus. | a captive colony of collared lemmings (dicrostonyx groenlandicus) from northern alaska produced a male-biased sex ratio of 67% males for about three generations. these lemmings have a pair of autosomes fused to the sex chromosomes. thus, males have two copies of some (formerly autosomal) sex-linked genes: one set is x-linked; the other can be described as y-linked. given such a karyotype, deleterious recessive alleles on the autosomal portion of the x chromosome are more resistant to selection t ... | 1995 | 8598343 |
| highly overlapping winter diet in two sympatric lemming species revealed by dna metabarcoding. | sympatric species are expected to minimize competition by partitioning resources, especially when these are limited. herbivores inhabiting the high arctic in winter are a prime example of a situation where food availability is anticipated to be low, and thus reduced diet overlap is expected. we present here the first assessment of diet overlap of high arctic lemmings during winter based on dna metabarcoding of feces. in contrast to previous analyses based on microhistology, we found that the die ... | 2015 | 25635852 |
| response of an arctic predator guild to collapsing lemming cycles. | alpine and arctic lemming populations appear to be highly sensitive to climate change, and when faced with warmer and shorter winters, their well-known high-amplitude population cycles may collapse. being keystone species in tundra ecosystems, changed lemming dynamics may convey significant knock-on effects on trophically linked species. here, we analyse long-term (1988-2010), community-wide monitoring data from two sites in high-arctic greenland and document how a collapse in collared lemming c ... | 2012 | 22977153 |
| genome-wide comparative chromosome maps of arvicola amphibius, dicrostonyx torquatus, and myodes rutilus. | the subfamily arvicolinae consists of a great number of species with highly diversified karyotypes. in spite of the wide use of arvicolines in biological and medicine studies, the data on their karyotype structures are limited. here, we made a set of painting probes from flow-sorted chromosomes of a male palearctic collared lemming (dicrostonyx torquatus, dto). together with the sets of painting probes made previously from the field vole (microtus agrestis, mag) and golden hamster (mesocricetus ... | 2016 | 26611440 |
| karotype of dicrostonyx torquatus chionapaes allen and an unusual chromosome mechanism of sex determination in palearctic pied lemmings. | | 1991 | 1204450 |
| influence of climate warming on arctic mammals? new insights from ancient dna studies of the collared lemming dicrostonyx torquatus. | global temperature increased by approximately half a degree (celsius) within the last 150 years. even this moderate warming had major impacts on earth's ecological and biological systems, especially in the arctic where the magnitude of abiotic changes even exceeds those in temperate and tropical biomes. therefore, understanding the biological consequences of climate change on high latitudes is of critical importance for future conservation of the species living in this habitat. the past 25,000 y ... | 2010 | 20523724 |
| [the characteristics of the formation of the hypothalamo-hypophyseal neurosecretory system in the arctic lemming dicostonyx torquatus of wrangel island in the postnatal development period]. | hypothalamo-hypophyseal neurosecretory system (hhns) of 1-30 days old lemmings dicrostonyx torquatus from the wrangel island in the year of a decreased but still highly dense population was studied by paraldehyde fucshin method and immunohistochemically using antisera to vasopressin and oxytocin. in the period of first two weeks of postnatal development the rate of hhns formation was found to have significant individual differences and to be slower than hhns formation in laboratory rats due to l ... | 1996 | 9148617 |
| [histological and ultrastructural analysis of the adrenal cortex of the wrangel island hoofed lemming (dicrostonyx torquatus vinogradovi ognev, 1948)]. | structure of the adrenal cortex of the lemming (dicrostonyx torquatus vinogradovi ognev, 1948) from the wrangel island has been studied light optically and electron microscopically. histological investigation of the adrenals has revealed some peculiar features in the gland demonstrating a moderate development of the reticular zone in both sex in the dicrostonyx torquatus, as well as certain sex dimorphism in the organ's structure. a smaller specific gravity of the female glomerular zone, divisio ... | 1981 | 7028001 |
| [ultrastructure of the median eminence and posterior lobe of the hypophysis in newborn diocrostonyx torquatus lemmings during a decline in the population count]. | electron microscopically using morphometric analysis, the median eminence and hypophysis posterior lobe have been studied in newborn lemmings (dicrostonyx torquatus pallas) at the stage of decreasing population. a comparative characteristics of capillaries in the primary plexus of the portal system and capillaries of the hypophysis posterior lobe is presented. overtaking developmental rate is demonstrated in the posterior hypophyseal lobe in comparison to that of the median eminence. in the lemm ... | 1987 | 3322236 |
| encephalitozoonosis in arctic lemmings. | encephalitozoonosis was identified for the first time in arctic lemmings (dicrostonyx stevensoni and crosses of d. stevensoni and dicrostonyx rubricatus). the most common clinical findings were circling, torticollis, posterior paralysis, depression, blindness and death related to parasitic granulomas in many tissues. granulomas were most frequent in the central nervous system, but were seen in many other tissues throughout the body. granulomas were characterized by collections of macrophages and ... | 1989 | 2474690 |
| [morphofunctional features of the development of the thyroid gland of dicrostonyx torquatus during the drop in population stage]. | by means of the histostereometrical method, peculiarities of the thyroid gland formation have been studied in the lemming (dicrostonyx torquatus) fetuses and newborns at the stage of the population quantity drop, as well specificity of the organ's morphofunctional state during the postnatal period. on the 14th prenatal day the thyroid gland already has the follicular structure. up to the 19th day progressive follicular growth, accumulation of colloid and increase of its density occur. on the 19t ... | 1987 | 3551885 |
| [features of the development of the pituitary-thyroid system of the wrangel island hoofed lemming dicrostonyx torquatus at stages of growth and peak population]. | by means of morphometric techniques, peculiarities in formation of the hypophyseal-thyroid system during prenatal and early postnatal periods have been studied in lemmings (dicrostonyx torquatus) from the wrangel island at growth stages and at the peak of the population quantity. folliculoformation rate, time when the organ reaches the definitive structure, periods for establishing connection with the regulating center--the anterior hypophyseal lobe, correlation of differentiation rates of histo ... | 1986 | 3548654 |
| [follicular epithelium of the ovary in the prenatal and early postnatal periods of ontogenesis of the wrangell island lemming dicrostonyx torquatus pall]. | in 69 representatives of the arctic lemming the ovaries have been studied. morphologucal peculiarities of prefollicular and follicular cells have been revealed during various periods of folliculogenesis, as well as changes in the volumetric density arrangement of cellular organells in the process of their differentiation. it is supposed that during the period preceding formation of the follicles (15.5-20 days of embryonal development and the first three days after birth) the prefollicular cells ... | 1985 | 3901964 |
| the hypothalamo-hypophysial system of the lemming, dicrostonyx torquatus pallas. ii. seasonal changes in the gomori-positive neurosecretory centers of the hypothalamus and posterior pituitary (an ultrastructural study). | | 1985 | 3909678 |
| the hypothalamo-hypophyseal system of the lemming, dicrostonyx torquatus pallas. i. seasonal changes in the neurosecretory system during years of various reproductive efficiency. | | 1984 | 6395531 |
| [estrous cycle of the arctic lemming (dicrostonyx torquatus pall.) maintained and breeding under laboratory conditions]. | reproductive functions and life at laboratory conditions were studied in the lemming. standard cage-terrariums with a wheel for motion and a plate for drinking are quite convenient. the main ration includes: hay, oats with some carrot added, some apples two--three times a week, sunflower seeds. the animals feel well and reproduce at +8 degrees and +20 degrees in well ventilated rooms. the estrous cycle in lemming females studied by microscopy of vaginal smears is not regular. only two stages are ... | 1979 | 454196 |
| [a comparative study of dicrostonyx torquatus chionopaes allen dna with different numbers of b-chromosomes]. | in order to elucidate the possible relationship between the karyotype and the polynucleotide sequence organization in dna, comparison was made between dna from the liver of dicrostonyx torquatus chionapaes allen with different numbers of b-chromosomes (2n = 47-49, 1-3 b-chromosomes; 2n = 52-54,6-8 b-chromosomes). the reassociation kinetics patterns for denatured dna fragments (about 300 nucleotides long) were obtained by the batch hydroxyapatite method. the analysis of these patterns showed a ap ... | 2006 | 745607 |
| ectoparasites of the collared lemming (dicrostonyx torquatus) on bathurst island, n.w.t., canada. | | 1977 | 561848 |
| [experimental study of susceptibility and infectious sensitivity to tularemia of the lemming (dicrostonyx torquatus pall]. | complex study demonstrated high susceptibility and infectious sensitivity of dicrostonyx torquatus pall. to the causative agent of tularemia, and its reference to the 1-st group of mammals (according to olsufiev). | 1976 | 1007735 |
| [b-chromosomes, unusual inheritance of sex chromosomes and sex ratio in the pied lemming dicrostonyx torquatus torquatus pall. 1779]. | | 1973 | 4778974 |
| trypanosomiasis in the collared lemming, dicrostonyx torquatus (rodentia). | | 1955 | 13272107 |
| cecal villi in dicrostonyx torquatus (rodentia: microtinae). | | 1955 | 13268898 |
| demographic responses of a site-faithful and territorial predator to its fluctuating prey: long-tailed skuas and arctic lemmings. | environmental variability, through interannual variation in food availability or climatic variables, is usually detrimental to population growth. it can even select for constancy in key life-history traits, though some exceptions are known. changes in the level of environmental variability are therefore important to predict population growth or life-history evolution. recently, several cyclic vole and lemming populations have shown large dynamical changes that might affect the demography or life ... | 2014 | 24128282 |
| intrachromosomal rearrangements in rodents from the perspective of comparative region-specific painting. | it has long been hypothesized that chromosomal rearrangements play a central role in different evolutionary processes, particularly in speciation and adaptation. interchromosomal rearrangements have been extensively mapped using chromosome painting. however, intrachromosomal rearrangements have only been described using molecular cytogenetics in a limited number of mammals, including a few rodent species. this situation is unfortunate because intrachromosomal rearrangements are more abundant tha ... | 2017 | 28867774 |
| assessing stress in arctic lemmings: fecal metabolite levels reflect plasma free corticosterone levels. | interest in the ecology of stress in wild populations has triggered the development of noninvasive methods for quantifying stress hormones. measurement of fecal corticosteroid metabolites (fcms) is one such method, but it is still unclear whether fcms can be a reliable proxy of free plasma glucocorticoids. to assess the validity of this assumption, we carried out a robust assessment on brown lemmings (lemmus trimucronatus) from bylot island, nunavut, canada, that were hand captured and anestheti ... | 2017 | 28384423 |
| complete mitochondrial genome of the eurasian collared lemming dicrostonyx torquatus pallas, 1779 (rodentia: arvicolinae). | the complete mitochondrial genome the eurasian collared lemming was obtained by using pcr amplification and capillary sequencing (genbank accession no. kx066190). the collared lemming mitochondrial genome is 16,340 base pairs long and shows the gene order, contents and gene strand asymmetry typical for mammals. the mitogenome sequence provides an important new genomic resource for the collared lemming, which is a model study species in arctic phylogeography and biotic history. | 2016 | 28670624 |
| indirect food web interactions mediated by predator-rodent dynamics: relative roles of lemmings and voles. | production cycles in birds are proposed as prime cases of indirect interactions in food webs. they are thought to be driven by predators switching from rodents to bird nests in the crash phase of rodent population cycles. although rodent cycles are geographically widespread and found in different rodent taxa, bird production cycles appear to be most profound in the high arctic where lemmings dominate. we hypothesized that this may be due to arctic lemmings inducing stronger predator responses th ... | 2013 | 24173526 |
| lemming winter habitat choice: a snow-fencing experiment. | the insulative value of early and deep winter snow is thought to enhance winter reproduction and survival by arctic lemmings (lemmus and dicrostonyx spp). this leads to the general hypothesis that landscapes with persistently low lemming population densities, or low amplitude population fluctuations, have a low proportion of the land base with deep snow. we experimentally tested a component of this hypothesis, that snow depth influences habitat choice, at three canadian arctic sites: bylot islan ... | 2012 | 22042523 |
| from arctic lemmings to adaptive dynamics: charles elton's legacy in population ecology. | we shall examine the impact of charles s. elton's 1924 article on periodic fluctuations in animal populations on the development of modern population ecology. we argue that his impact has been substantial and that during the past 75 years of research on multi-annual periodic fluctuations in numbers of voles, lemmings, hares, lynx and game animals he has contributed much to the contemporary understanding of the causes and consequences of population regulation. elton was convinced that the cause o ... | 2001 | 11325052 |
| xo females in the varying lemming, dicrostonyx torquatus: reproductive performance and its evolutionary significance. | | 1982 | 28568045 |
| effects of cold exposure on urinary catecholamines in arctic lemmings. | | 1977 | 23926 |
| cold acclimation in arctic lemmings. | | 1976 | 4265 |
| high arctic lemmings remain reproductively active under predator-induced elevated stress. | non-consumptive effects of predation have rarely been assessed in wildlife populations even though their impact could be as important as lethal effects. reproduction of individuals is one of the most important demographic parameters that could be affected by predator-induced stress, which in turn can have important consequences on population dynamics. we studied non-consumptive effects of predation on the reproductive activity (i.e., mating and fertilization) of a cyclic population of brown lemm ... | 2018 | 29651661 |
| impact of past climate warming on genomic diversity and demographic history of collared lemmings across the eurasian arctic. | the arctic climate was warmer than today at the last interglacial and the holocene thermal optimum. to reveal the impact of past climate-warming events on the demographic history of an arctic specialist, we examined both mitochondrial and nuclear genomic variation in the collared lemming (dicrostonyx torquatus, pallas), a keystone species in tundra communities, across its entire distribution in northern eurasia. the ancestral phylogenetic position of the west beringian group and divergence time ... | 2020 | 31988125 |
| are gastrointestinal parasites associated with the cyclic population dynamics of their arctic lemming hosts? | many rodents, including most populations of arctic lemmings (genus dicrostonyx and lemmus), have cyclic population dynamics. among the numerous hypotheses which have been proposed and tested to explain this typical characteristic of some terrestrial vertebrate communities, trophic interactions have often been presented as the most likely drivers of these periodic fluctuations. the possible role of parasites has, however, only seldom been assessed. in this study, we genetically measured the preva ... | 2019 | 31321206 |