Major Regularities of Transformation of the Small Mammal Ovaries in Unfavourable Environmental Conditions: Ecological and Morphological Aspects

The aim of the study was to determine the patterns of structural and functional organization of the ovaries of female small mammals inhabiting technogenically altered ecosystems.Material and methods. We studied the ovaries of small mammal species belonging to the insectivore and rodent families (common shrew, field and pygmy wood mice, common and bank voles, mole vole, steppe pied) that live in anthropogenically altered ecosystems (zones of influence of ferrous and nonferrous metallurgy, as well as gas processing factory). The resulting material was processed using observational histological, histochemical, immunohistochemical and morphometric tests.Results. The results obtained demonstrated that in technogenically altered ecosystems the intensified reproduction results in a complex of morphofunctional reactive and adaptive changes in the ovaries of females of the studied species. The size of the ovaries was reduced; the area of the cortical substance was reduced. In the cortex, there was revealed a decrease in the number of follicles varying over a wide range - from a moderate decrease to their almost complete absence. There was found a decrease in the area of the vessels of the microvasculature; this was one of the major reasons for the increased follicular atresia. In follicles of various types, there was an increase in the proportion of cells expressing the proapoptotic protein P53. A decrease in the number of follicles resulted in the connective tissue overgrowth. The presence of cysts lined with epithelium of various heights was revealed in the cortex and medulla. Conclusion. The results obtained evidence that in technogenically altered ecosystems a decreased ovarian reserve is observed in the ovaries of female small mammals; it is associated with a more rapid depletion of the follicle reserve in the cortex due to both - intensification of reproduction and more rapid death of follicles in unfavourable environmental conditions.

Commensals of underground mammals: European mole (Talpa europaea, Eulipotyphla, Talpidae) and the greater mole-rat (Spalax microphthalmus, Rodentia, Spalacidae)

Stepanova I, Andreychev A, Kulakhmetov R, Lobachev E. 2021. Commensals of underground mammals: European mole (Talpa europaea, Eulipotyphla, Talpidae) and the greater mole-rat (Spalax microphthalmus, Rodentia, Spalacidae). Biodiversitas 22: 4665-4670. The study of lodgers of burrows of underground mammals was carried out using the method of hunting cylinders (cans). In the study, 29 different representatives from the following classes were identified in the courses of the greater mole-rat and European mole: Diplopoda, Chilopoda, Gastropoda, Insecta, Amphibia, and Mammalia. Among the vertebrates captured are Eurasian common shrew (Sorex araneus), Eurasian pygmy shrew (Sorex minutus), bank vole (Clethrionomys glareolus), common spadefoot toad (Pelobates fuscus), moor frog (Rana arvalis), and common toad (Bufo bufo). Twenty-six different species have been identified among invertebrates. Many animals seek shelter in the burrows of underground mammals from enemies and adverse climatic factors for food or conditions for reproduction. In the central part of Russia, more species of commensals were found in European mole burrows (29) than in greater mole-rat burrows (21).

Demodex crocidurae, a New Demodecid Mite (Acariformes: Prostigmata) Parasitizing the Lesser White-Toothed Shrew and a Redescription of Demodex talpae from European Mole with Data on Parasitism in Soricomorpha

Only six parasitic species of Demodecidae mite have thus far been described from the Soricomorpha, these being associated with the common shrew Sorex araneus Linnaeus, 1758, and the Mediterranean water shrew Neomys anomalus Cabrera, 1907 (two species from each host), and with the lesser white-toothed shrew Crocidura suaveolens (Pallas, 1811) and the European mole Talpa europaea Linnaeus, 1758 (one from each host species). Presently, Demodex crocidurae, a new species, has been described from the territory of Poland for C. suaveolens; in order to confirm its validity, it was necessary to redescribe D. talpae Hirst, 1921, from T. europaea, a demodecid species first described by Hirst in 1921 from England and then noted only in Poland. Both species colonized the hairy skin of the body in their hosts, where no disease symptoms of infestation were observed. However, D. crocidurae showed higher infection parameters (prevalence 100%, mean intensity 11.7, intensity range 3–26 individuals) than those of D. talpae (30.0%, 4.7, 2.0–8.0), possibly due to different host biology.

Lunar illumination shapes small mammal activity in lowland agricultural landscapes

The behavioural patterns of small mammalian prey species have been shown to be widely impacted by predator avoidance. Cues to avoid predation may come from the predator itself or environmental cues, such as moonlight and available vegetative cover. We investigated how the activity of the bank vole Myodes glareolus, field vole Microtus agrestis, wood mouse Apodemus sylvaticus and the common shrew Sorex araneus were impacted by changes in habitat and lunar light conditions across a range of habitats (mainly grassland protected sites) in Lincolnshire (UK). Microhabitat vegetation density as well as weather conditions were recorded across all trap sites, with Longworth traps set overnight and the successfully captured species recorded the following morning. Overnight temperature was found to positively influence capture rate across all species. The lunar phase was found to significantly impact capture rate, with the gibbous lunar phase providing the highest capture rate across species. The interaction between illumination and vegetation density was also found to impact activity levels in the bank vole and wood mouse, with the bank vole showing higher activity in thick vegetation at low light levels and across habitats at higher light levels, whereas wood mice were more often captured in intermediate cover at low and intermediate illumination but across a range of habitats at brighter illumination. In combination, it suggests that small mammal activity is altered to potentially reduce predation risk. However, in this community at least, brighter lunar illumination leads to increase activity.

Geographic Distribution and Phylogeny of Soricine Shrew-Borne Seewis Virus and Altai Virus in Russia

The discovery of genetically distinct hantaviruses (family Hantaviridae) in multiple species of shrews, moles and bats has revealed a complex evolutionary history involving cross-species transmission. Seewis virus (SWSV) is widely distributed throughout the geographic ranges of its soricid hosts, including the Eurasian common shrew (Sorex araneus), tundra shrew (Sorex tundrensis) and Siberian large-toothed shrew (Sorex daphaenodon), suggesting host sharing. In addition, genetic variants of SWSV, previously named Artybash virus (ARTV) and Amga virus, have been detected in the Laxmann’s shrew (Sorex caecutiens). Here, we describe the geographic distribution and phylogeny of SWSV and Altai virus (ALTV) in Asian Russia. The complete genomic sequence analysis showed that ALTV, also harbored by the Eurasian common shrew, is a new hantavirus species, distantly related to SWSV. Moreover, Lena River virus (LENV) appears to be a distinct hantavirus species, harbored by Laxmann’s shrews and flat-skulled shrews (Sorex roboratus) in Eastern Siberia and far-eastern Russia. Another ALTV-related virus, which is more closely related to Camp Ripley virus from the United States, has been identified in the Eurasian least shrew (Sorex minutissimus) from far-eastern Russia. Two highly divergent viruses, ALTV and SWSV co-circulate among common shrews in Western Siberia, while LENV and the ARTV variant of SWSV co-circulate among Laxmann’s shrews in Eastern Siberia and far-eastern Russia. ALTV and ALTV-related viruses appear to belong to the Mobatvirus genus, while SWSV is a member of the Orthohantavirus genus. These findings suggest that ALTV and ALTV-related hantaviruses might have emerged from ancient cross-species transmission with subsequent diversification within Sorex shrews in Eurasia.

Population of small terrestrial vertebrates of the nature monument “Cheuskinsky bor” (Khanty-Mansi autonomous okrug – Yugra)

There are 25 specially protected natural areas of various status have been organized on the territory of the Khanty-Mansiysk Autonomous Okrug Ugra. Despite their great nature conservation value, the degree of study of flora and fauna, as well as the ecology of plants and animals in the territory of most of them, remains relatively low. Until now, special studies of small terrestrial vertebrates inhabiting the Cheuskinsky Bor have been carried out. In 2020, our research of small terrestrial vertebrates were carried out. The purpose of the study is to identify the species composition and some features of ecology (abundance, biotopic distribution) of small mammals, amphibians and reptiles. The research was carried out in July-September 2020. Metal cones were used to catch most of the vertebrate species. A total of 7400 cone-days have been worked out. 10 species of small mammals and 3 of amphibians are registered. The species composition of small mammals at the Cheuskinsky Bor site is relatively poor, 10 species were captured by cones, 3 were marked visually. The group of dominants included the common shrew and the red-backed vole. They accounted for 22% and 77%, respectively, of all recorded animals. Reptiles in the 2020 season were not registered in the counts, however, according to the literature, the habitat of the common European adder and viviparous lizard is known. Among amphibians, the moor frog and Siberian salamander are rare, the European toad is common. In the future, when conducting annual studies, the list of small mammals can be supplemented by 714 species of insectivores, bats and rodents, the list of amphibians 1 species.