Nina Bulakhova

Russian Academy of Sciences | RAS · Institute of Biological Problems of the North

The cold tolerance, the attitude to dissolved oxygen depletion in water, and the overwintering strategy of individuals of one of the intraspecies forms of the Oriental fire-bellied toad, Bombina orientalis f. sylvatica were studied in the south of Primorye, Russian Far East. It was revealed that individuals of the study form were unable to tolerate...

Seasonal variation in the amount of fluid in the subcutaneous lymphatic sinuses of the common frog (Rana temporaria) and differences in the dynamics of its mass in adult males and females from autumn to spring are shown. The hypothesis that enlarged lymphatic sinuses (one of the elements of the “nuptial attire” of R. temporaria) can be used by smal...

The Siberian moth, Dendrolimus sibiricus Tschetverikov 1908, is a dangerous pest of the conifer family Pinaceae that inhabits the Asian part of Russia, northern Kazakhstan, Mongolia, China and the Korean Peninsula. Its range is gradually expanding both westwards and northwards: the species is currently recorded at 46°–47° E over the Eastern Europea...

The Pallas’ spadefoot Pelobates vespertinus is a frog species native to eastern Europe and west Siberia. This species resists harsh winter conditions by moving up to 2 m underground. This amphibian is the first species known to withstand extreme air hypoxia. In this study, we investigated the metabolome of liver, heart, and brain of the Pallas’ spa...

Squamate reptiles are central for studying phenotypic correlates of evolutionary transitions from oviparity to viviparity because these transitions are numerous, with many of them being recent. Several models of life‐history theory predict that viviparity is associated with increased female size, and thus more female‐biased sexual size dimorphism (...

The Siberian frog Rana amurensis has a uniquely high tolerance to hypoxia among amphibians, as it is able to withstand several months underwater with almost no oxygen (0.2 mg/liter) vs. several days for other studied species. Since it was hypothesized that hypoxia actives the antioxidant defense system in hypoxia-tolerant animals, one would expect...

In recent decades, the northern border of the Siberian moth (Dendrolimus sibiricus Tschetv.) range has shifted in Siberia to 60–63° N. However, it is difficult to predict the further species spread because of insufficient data on environmental stress factors, including the requirements of the species during winter conditions. We estimated the cold...

The predatory Asian harlequin ladybird Harmonia axyridis is an effective regulator of insect pests of agricultural plants. It has been widely introduced worldwide, but has become a threat to the biodiversity of native entomofauna. To assess its ability to colonize areas with cold winters, we determined the cold-hardiness of wintering adults of H. a...

Cold hardiness during wintering of the Asiatic toad Bufo gargarizans Cantor, 1842, the northernmost species of the family in the Russian Far East, was studied. The supercooling point (SCP) and low lethal temperature (LLT) were determined for sexually mature individuals. It was found out that the average SCP of acclimated animals was -3.5±0.1°C. At...

The Pallas’ spadefoot Pelobates vespertinus exhibits resilience to harsh winter conditions by burrowing up to a depth of 2 meters underground. Here we aimed to explore the metabolome of the Pallas’ spadefoot after a month-long exposure to air hypoxia (approximately 2% O2 content). Surprisingly, our findings revealed minimal differences when compare...

Anoxia is a significant challenge for most animals, as it can lead to tissue damage and death. Among amphibians, the Siberian frog Rana amurensis is the only known species capable of surviving near-zero levels of oxygen in water for a prolonged period. In this study, we aimed to compare metabolomic profiles of the liver, brain, and heart of the Sib...

The origin of the fauna of Beringia is a notable biogeographical puzzle. Large mussels of the genus Beringiana inhabit both Northeast Asia and the northwestern part of North America and thus provide an important model to investigate the paleobiogeography of Beringia and the past and current intercontinental species exchanges. Data on Beringiana dis...

Pallas’ spadefoot is a Eurasian species of amphibian that winters for about half a year at a depth to 200 cm, always below the level of freezing, since it does not survive negative temperatures. However, significantly digging into the soil can cause oxygen deficiency. The minimum sufficient for a long-term existence of Pelobates vespertinus and the...

Amphibians are believed to be sensitive to hypoxia, and in terms of this ability, they are between mammals with poor toleranсе to hypoxia and some turtles and fish with good tolerance to variable oxygen availability. However, we found that the Pallas’ spadefoot, Pelobates vespertinus (Pallas, 1771), a Eurasian anuran burrowing amphibian species, is...

Several earthworm species are known to be able to withstand freezing. At the biochemical level, this ability is based on cryoprotectant accumulation as well as several other mechanisms. In this study, we used ¹H NMR to investigate metabolomic changes in two freeze-tolerant earthworm taxa, Dendrobaena octaedra and one of the genetic lineages of Eise...

The geographic variability of the cold hardiness of poikilothermic animals is one of the keys to understanding the mechanisms of the formation of their ranges under climate change or anthropogenic introductions. A convenient object is the small tortoiseshell butterfly Aglais urticae, which is distributed from the Atlantic Ocean to the Pacific Ocean...

Drawida ghilarovi is an earthworm species with the northernmost distribution of all Monilidastridae in Asia. It includes multiple color morphs and has significant genetic diversity. In this study we used transcriptome sequencing to demonstrate that D. ghilarovi consists of three genetic clades that differ on both mitochondrial and nuclear genome le...

Among the factors contributing to the initiation of outbreaks of the Siberian moth, a dangerous pest of the coniferous forests of Northern Eurasia, it is considered important to reduce the regulatory impact of entomophages. One of the most effective regulators of the pest abundance is the egg parasitoid wasp Telenomus tetratomus (Thomson, 1861). Th...

The moor frog Rana arvalis is one of a few amphibians that can tolerate freezing to low temperatures, up to −16 °C. In this study, we performed metabolomic analysis of the liver and hindlimb muscles of frozen and control R. arvalis. We found that the moor frog synthesizes glucose and glycerol in similar concentrations as low molecular weight cryopr...

For the first time, the pre-hibernation sizes of “storage” organs (liver and fat bodies), the type, concentration and total content of reserve substances (glycogen or lipids) in these organs and muscle tissue, and their change during freezing in freeze tolerant specimens of the moor frog (Rana arvalis) in the Siberian population were studied. In au...

The Siberian wood frog Rana amurensis Boulenger, 1886 is the most hypoxia-tolerant amphibian. It can survive for several months in an almost complete absence of oxygen. Little is known about the mechanisms of this remarkable resilience, in part because studies of amphibian genomes are impeded by their large size. To make the Siberian wood frog more...

The geographic distribution of the common viper, Vipera berus (L. 1758), was believed to be limited in the north and northeast by an assumed lack of hibernacula with temperatures exceeding 0°C, because the species is not freeze-tolerant. To test this hypothesis, we measured in the laboratory the cold resistance of vipers that inhabit Kizhi Island (...

The Siberian salamander Salamandrella keyserlingii Dybowski, 1870 is a unique amphibian that is capable to survive long-term freezing at −55 °C. Nothing is known on the biochemical basis of this remarkable freezing tolerance, except for the fact that it uses glycerol as a low molecular weight cryoprotectant. We used 1H-NMR analysis to study quantit...

Biological diversity is the basis for, and an indicator of biosphere integrity. Together with climate change, its loss is one of the two most important planetary boundaries. A halt in biodiversity loss is one of the UN Sustainable Development Goals. Current changes in biodiversity in the vast landmass of Siberia are at an initial stage of inventory...

We studied resistance of the frog Rana macrocnemis Boulenger, 1885 from the highlands of the Republic of Dagestan (Russia) to negative temperatures and to hypoxia in water, which allow this frog species to overwinter on land or in water bodies. The average supercooling point (SCP) for R. macrocnemis is -2.1 °C. However, the state of supercooling is...

Eisenia nordenskioldi (Eisen, 1879) is the only autochthonous Siberian earthworm with a large distribution that ranges from tundra to steppe and broadleaved forests. This species has a very high morphological, ecological, karyological, and genetic diversity, so it was proposed that E. nordenskioldi should be split into several species. However, the...

Вскрыты причины, препятствующие восточно европейской амфибии-чесночнице Палласа (Pelobates vespertinus)-продвинуться в Азию далее долины Тобола. Она зарывается осенью в землю и тем избегает непереносимые ею отрицательные температуры зимовки. Меридиональ ных географических рубежей на восточной окраине ареала неизвестно. На карты нанесены средние мно...

The information concerning the origin, biogeography and dispersal mechanisms of sphaeriid species in the Holarctic region is very limited. In this study, we report on the first occurrence of Euglesa globularis in the Magadan Oblast. According to our molecular data, 16S RNA sequences of E. globularis are represented by two haplotypes, one of which i...

We studied the relationship between the geographic distribution of the Pallas' spadefoot (Pelobates vespertinus) and the soil temperature regime at the eastern boundary of this species' range (south-western West Siberia and northwest Kazakhstan). This species overwinters underground, burrowing down to 1.5 m or deeper and has poor frost tolerance-it...

The Siberian wood frog Rana amurensis is a recently discovered example of extreme hypoxia tolerance that is able to survive several months without oxygen. We studied metabolomic profiles of heart and liver of R. amurensis exposed to 17 days of extreme hypoxia. Without oxygen, the studied tissues experience considerable stress with a drastic decreas...

Only two species of boreal Holarctic frogs (genus Rana Linnaeus, 1758) can survive freezing and overwinter on land; they are found in the subarctic and cold regions of North America (Wood Frog, Rana sylvatica LeConte, 1825) and Eurasia (Moor Frog, Rana arvalis Nilsson, 1842) and are an example of an unusual adaptive strategy of overwintering. Freez...

It is difficult to determining the factors limiting the distribution of biological species in areas without pronounced geographic barriers. Exactly this kind of situation is with the eastern border of the range of the common frog (Rana temporaria), spreading in Western Siberia almost along the meridian between the Urals and the Ob River. According...

Siberian wood frog (Rana amurensis) is the northernmost species of anuran amphibians in Asia. What are the adaptations allowing it to live in the coldest regions of Siberia and the Far East? First, it was considered that the Siberian wood frog is one of the most cold�resistant amphibians (along with the Siberian salamander). However, this opinion t...

Reproductive mode, ancestry, and climate are hypothesized to determine body size variation in reptiles but their effects have rarely been estimated simultaneously, especially at the intraspecific level. The common lizard (Zootoca vivipara) occupies almost the entire Northern Eurasia and includes viviparous and oviparous lineages, thus representing...

Eisenia nordenskioldi is an earthworm widespread in Northern Asia and adjacent regions. It is known for its high morphological, karyotypic, and genetic variation, and contains two subspecies, the pigmented E. n. nordenskioldi and the unpigmented E. n. pallida. We obtained almost complete sequences of mitochondrial genomes (without the control regio...

Eisenia nordenskioldi is an earthworm widespread in Northern Asia and adjacent regions. It is known for its high morphological, karyotypic, and genetic variation, and contains two subspecies, the pigmented E. n. nordenskioldi and the unpigmented E. n. pallida. We obtained almost complete sequences of mitochondrial genomes (without the control regio...

Background: Pelobates fuscus is an anuran amphibian that overwinters on land deep in soil, including regions with low sub-zero temperatures. It is not yet known if such behaviour can be explained by low cold-hardiness of the species. Objective: To measure cold-hardiness of P. fuscus and compare the results with data about its location in winter...

Гигантские пространства Севера интересны для зоологов прежде всего экстремальными условиями, не пускающими сюда многих животных. Видовое разнообразие обитающих здесь постоянно (не сезонно) позвоночных невелико. Тем не менее тут живут даже амфибии, голые гады — по классификации позапрошлого века. Как они тут выживают, исследуют зоологи магаданского...

Few of the amphibian species that occur in the Subarctic and in mountains are adapted to low sub-zero temperatures; most of these species overwinter underwater. It is believed that the distribution of the species that overwinter underwater can be limited by the low oxygen levels in waterbodies covered with ice. We show that the colonisation of the...

Eisenia nordenskioldi subsp. nordenskioldi is an earthworm species inhabiting a large part of Asia, from approximately the 40° of north latitude to the shores of the Arctic Ocean. This taxon is known to have very high genetic diversity and contains several cryptic genetic lineages. In this study, we investigated phylogeography of E. n. nordenskiold...

Earthworms are an important component of soil fauna even in high latitudes, in the taiga and tundra biomes. It is yet unclear if earthworm populations from these regions are autochtonous or recent invaders. We collected earthworms from approximately from 64° to 73°N from the Kola Peninsula to Chukotka and genotyped it using the COI gene. We found D...

Adaptive strategies of the common frog, Siberian wood frog and Dybovsky’s frog (Rana temporaria, R. amurensis, R. dybowskii) in relation to winter temperature was studied. They all tolerate only small negative temperatures in a state of supercooling and die during the next freezing. A threshold of long-term (10 days) tolerated temperatures appears...

In cold the climate of the northern coast of the Sea of Okhotsk, the activity season of the Siberian salamander (mid-May through September) is not sufficient for completing the development of all oocytes that have reached the late stages of oogenesis: in late August, almost half of follicles with diameter over 0,5 mm remain in the stages of yolk (v...

Earthworms are a widespread and ecologically important group of animals, which has the highest total biomass in some ecosystems and often defines the composition of soil fauna. Earthworms are known to have high cryptic genetic diversity. In this study we attempted to estimate earthworm species diversity in the south of West Siberia by DNA barcoding...

The common lizard Zootoca vivipara has the largest range of all the terrestrial reptiles which includes the subarctic regions of the Palaearctic. The species provides a unique model for studying the strategies of adaptation of a reptile to extreme low winter temperatures. The aim of our research was to determine whether this species survives the se...

Дальневосточная квакша, представитель маньчжурской фауны, обладает выдающейся устойчиво- стью к отрицательным температурам среди исследованных бесхвостых амфибий. Почти 70% особей из популяции со Среднего Амура выдерживает охлаждение до –30°C, часть животных – до –35°C. Это более чем в два раза превышает возможности лесной лягушки (Lithobates sylva...

The Japanese tree frog, a representative of the Manchurian fauna, is characterized by an outstanding cold resistance among the anuran amphibian species studied so far. Almost 70% of the specimens from the population inhabiting the middle Amur River withstand the cooling down to–30°C; some animals, down to–35°C. This exceeds more than twofold the co...

Eisenia nordenskioldi pallida Malevič 1956 (Lumbricidae, Annelida) is widely distributed in various climatic zones of Northern Asia. To study its genetic variation, we collected specimens of this taxon from various populations throughout its distribution and sequenced mitochondrial (cox1) and nuclear (ITS2) loci. Five cryptic genetic lineages were...

Сибирский углозуб в замерзшем состоянии благополучно переносит длительное пребывание (45 сут) при температуре –35°С. Кратковременное (3 сут) охлаждение до –50°C выдерживают 40% взрослых особей, до –55°С – 80% сеголеток. За время подготовки к зимовке (температуры до 0°С) и в процессе замерзания (до –5°С) углозубы теряют в среднем около 28% массы тел...

A hypothesis of range formation of the earthworm Eisenia sibirica Perel et Graphodatsky 1984, which is an endemic species of the Altai–Sayan mountain system and is also found on the adjacent plains of Siberia across the valleys of the rivers, is suggested. The limited distribution of the species can be connected with the insufficient cold hardiness...

Range formation hypothesis of the earthworm Eisenia sibirica Perel et Graphodatsky, 1984, endemic of Altai-Sayansk mountain system, penetrating to the adjacent plains of Siberia across the valleys of the rivers, was suggested. Limited distribution of the species can be connected with insufficient cold hardiness of the worm stage (-10…-12°С). Foothi...

Earthworms are a widespread and ecologically important group of animals, which has the highest total biomass in some ecosystems and often defines the composition of soil fauna. Earthworms are known to have high cryptic genetic diversity. In this study we attempted to estimate earthworm species diversity in the south of West Siberia by DNA barcoding...

The sexual cycle of Siberian salamander females (Salamandrella keyserlingii Dybowski 1870) has been studied in the tundra of the northern coast of the Sea of Okhotsk. Spawning starts soon after the end of wintering (in the second half of May) and ends up in the first half of June. At the end of June, the ovaries show obvious features of a new ovoge...

The sexual cycle of males of Siberian salamander (Salamandrella keyserlingii Dybowskii 1870) was studied in tundras of the northern coast of the Sea of Okhotsk. During the activity season of individuals lasting for 4-4.5 months (from the beginning of May), the time of the development of gametes does not exceed 3 months. Primary spermatogonia are pr...

The integral influence of harsh climatic conditions on the main ecological characteristics (seasonal and diurnal activities, dynamics of the sex–age structure, fecundity of females and its variation in different waterbodies, etc.) of the Siberian salamander (Salamandrella keyserlingii Dybowski 1870) was studied in populations from two types of wate...

The fecundity-advantage-hypothesis (FAH) explains larger female size relative to male size as a correlated response to fecundity selection. We explored FAH by investigating geographic variation in female reproductive output and its relation to sexual size dimorphism (SSD) in Lacerta agilis, an oviparous lizard occupying a major part of temperate Eu...

The adaptations which allowed the Siberian salamander (Salamandrella keyserlingii Dybowski, 1870) to form its exceptionally large, polyzonal range (forest-steppe, forests, and southern tundras of Siberia and part of European Russia) remain insufficiently studied. We checked the hypothesis that S. keyserlingii was able to colonize the northern terri...

We studied cold resistance of Lumbricus rubellus, Octolasion lacteum, Dendrodrilus rubidus tenuis earthworms of Western Siberia (Tomsk) populations. Worms of these species turned out to be not resistant to low temperatures (100% mortality at −3 °C), while cocoons, on the contrary, survived −35 °C (L. rubellus) or below −40 °C (D. rubidus tenuis). T...

The reproductive system of 319 individuals of the Schrenckii salamander (Salamandrella schrenckii Strauch 1870) (synonym S. tridactyla sensu (Kuz’min et al., 2008) from a Khabarovsk population has been studied before wintering and during the spawning of animals. In the fall, all adult males had enlarged testes filled with bundles of spermatozoa and...

The European common lizard, Zootoca vivipara, is the most widespread terrestrial reptile in the world. It occupies almost the entire Northern Eurasia and includes four viviparous and two oviparous lineages. We analysed how female snout-vent length (SVL), clutch size (CS), hatchling mass (HM), and relative clutch mass (RCM) is associated with the re...

The snout-vent length (SVL) in females of the common lizard (Zootoca vivipara Jacq. 1787) was revealed to depend significantly on its physiological condition. In the second half of pregnancy in all the investigated individuals (n=88;63.0±0.4, 54.6-71.1 mm), SVL was significantly greater (t= 19.9, p≤ 0.001), than that in the individuals killed short...

The reproductive system in 319 individuals of Schrenckii salamanders (Salamandrella schrenckii Strauch 1870) from a Khabarovsk population has been studied before wintering and during the spawning of animals. In autumn, all adult males had enlarged testes filled with bundles of spermatozoa and no spermatozoa in the spermaducts. Females had large pig...

Abstract—The reproductive system of 319 individuals of the Schrenckii salamander (Salamandrella schrenckii Strauch 1870) (synonym S. tridactyla sensu (Kuz’min et al., 2008) from a Khabarovsk population has been studied before wintering and during the spawning of animals. In the fall, all adult males had enlarged testes filled with bundles of sperma...