In China, a joint Chinese-Russian scientific laboratory was opened in Heilongjiang province to preserve and restore the Amur tiger population. The laboratory appeared thanks to the support of two leading organizations in the field of research and wildlife conservation - the Center for the Study of Felidae at the Chinese Northeastern University of Forestry and the A.N. Institute of Ecology and Evolution A.N. Severtsov RAS (IPEE RAS). As part of the work, the laboratory plans to create a gene library of Amur tigers and Far Eastern leopards, monitor and study diseases of wild animals, and also observe the behavior of Amur tiger cubs. “The Amur tiger and the Amur leopard have been returning to China in recent years, primarily due to conservation measures in the Russian Federation. Wild animals know no boundaries, and they need to be studied and preserved together with our Chinese colleagues. We hope that joint research within the framework of the newly created laboratory will allow us to save the tiger in Russia and China,” said the director of the Institute of Ecology and Evolution of the Russian Academy of Sciences, corresponding member of the Russian Academy of Sciences, Doctor of Biological Sciences Sergey Valerievich Naidenko. You can see all the photos by following the link. Related materials: Xilhua News: "China and Russia have established a joint laboratory for the conservation and restoration of Amur tigers" Russian China: "China and Russia have created a joint laboratory for the conservation and restoration of Amur tigers" Greater Asia: "A Russian-Chinese laboratory for the conservation of the Amur tiger has opened in China"

At the end of 2023, within the framework of cooperation between the A.N. Severtsov Institute of Ecology and Evolution RAS and Nizhny Novgorod K. Minin State Pedagogical University, second year student Polina Nikolaevna Tyutyaeva completed a scientific internship at the Laboratory of Ecology of Aquatic Communities and Invasions under the guidance of A.A. Kotova, A.N. Neretina and P.G. Gharibyan. The material for the internship was hydrobiological samples taken from small reservoirs of the Nizhny Novgorod region in the fall of 2022 and 2023. During her internship, Polina Nikolaevna successfully mastered the identification of cladoceran crustaceans to the level of species or group of species using domestic and foreign identification keys based on light and scanning electron microscopy data. Polina Nikolaevna used the skills and abilities acquired at the Institute of Ecology and Evolution of the Russian Academy of Sciences when organizing a school research project on the topic “Cradocera (Crustacea: Cladocera) as an indicator of environmental changes in some small reservoirs of the Nizhny Novgorod region.” This work was carried out by Polina Korneva, a student of the Municipal Budgetary Educational Institution “School No. 130”, under the guidance of P.N. Tyutyaeva. On March 22, 2024, two Polinas successfully presented their project in the finals of the regional stage of the All-Russian competition “Great Challenges”, aimed at involving talented youth in scientific and technological activities. Based on the selection results, Polina Korneva advanced to the next (federal) stage of the competition and will defend her project at the Sirius educational center. The team of the Laboratory of Aquatic Communities and Invasions congratulates the young hydrobiologists on their victory and wishes them inspiration and luck in the study of Nizhny Novgorod water fleas!

Fig.1: Russian scientists began naming whales about 25 years ago. Photo: Anastasia Kunitsa About 400 bowhead and 400 gray whales live in the waters of the Sea of Okhotsk. And almost each of them has their own name or funny nickname. Thus, in whale catalogs compiled by mammal specialists, you can find “tailed animals” named Korovka (Cow), Tigrenok (Tiger Cub), Galaktika (Galaxy), Tetris (Tetris) and Dedushka (Grandfather). Komsomolskaya Pravda figured out how and why whales are given such unusual names. The color and scars as scientific data In Russia, whales have been given names since about 25 years ago. Then mammal experts began compiling whale catalogs and identifying gray whales. Teams of scientists from the  A.N. Severtsov Institute of Ecology and Evolution are actively engaged in the study of cetaceans. Fig.2: Example from the whale catalog. Photo: provided by Anastasia Kunitsa The main way to study cetaceans is photo identification. Specialists photograph whales using drones or during expeditions, assign them a serial number, give them names and enter data into a whale catalog. Along with photographs, the animal's card also indicates the date and place of the first and last sighting. More detailed data is stored electronically in tables, explains Anastasia Kunitsa, a specialist in the study of mammals at the Institute of Ecology and Evolution of the Russian Academy of Sciences. Fig.3: Anastasia Kunitsa goes on expeditions to study gray whales. Photo: provided by Anastasia The easiest creatures to study and identify are bowhead and gray whales that live in the Sea of Okhotsk, as well as humpback whales in the Far East, as they have characteristic patterns on their bodies. It is these species that scientists most often give names to. Other types of whales, for example beluga whales or blue whales, rarely have color features, so it is much more difficult to distinguish between them. - Experts give names to whales primarily for convenience in communicating with each other. That is, in official documents and scientific publications we note that we saw whale number 123, and among ourselves we say: “Oh, Valera has arrived!” says Anastasia Kunitsa. - Scientists often name sea creatures after their loved ones. For example, I have a favorite gray whale – Matveyushka. He has a reddish coloring, so I named him in honor of my red-haired friend Matvey. We named one whale Brother Nikolai. Our volunteer really asked to name the sea creature in honor of his brother, but since Nikolai was already in the catalog, they gave him this unusual name,” says Anastasia Kunitsa. Fig.4: Korovka (Cow) has a characteristic scar that resembles the image of a cow. Photo: courtesy of IEE RAS But most often, scientists come up with funny nicknames based on associations with spots, scars or scratches on the body of sea creatures. - We have a gray whale, Tigrenok (Tiger Cub), who had tears on his back, possibly from ship propellers, that left scars in the form of even stripes. Bowhead whales have many interesting patterns and markings on their bodies. For example, Dedushka (Grandfather) got his name due to depigmentation, the so-called “gray hair”. Smurfik (Smurf) was named according to the same principle. His “gray hair” on the blades of his tail is very reminiscent of a gnome in a cap. Serdechko (Heart) has a scar right on the blowhole (the nostrils of a whale) that resembles an inverted heart, and Korovka (Cow) has a scar exactly like a cow,” explains Maria Slavina, a biologist at the Institute of Ecology and Evolution of the Russian Academy of Sciences. Fig.5: Dedushka (pictured left) got his name due to the depigmentation, the so-called “gray hair” on the upper part of the body. Smurfik (right) was given this name because the “gray hair” on his blades looks like a gnome. Photo: courtesy of IEE RAS Scientists from different research groups share data collected during whale identification in joint projects. The names of marine inhabitants rarely appear in scientific articles and publications. In reports, scientists usually indicate only the number of individuals that they were able to study during the season. But in some cases, individual whales do become celebrities and make headlines. Fig.6: Pomponchik (pompom) got its name thanks to the spots on its blowhole. Photo: courtesy of IEE RAS Fig.7: The whale named Most Zolotye Vorota (Golden Gate Bridge) has markings of the famous landmark on the right blade of its tail. Photo: courtesy of IEE RAS Fig.8: Lyagushka (frog) was named after an unusual scar on the left blade of its tail. Photo: courtesy of IEE RAS - This was the case with the female whale Varvara, on whom scientists installed a tracking sensor. In 2011, she migrated to Mexico and returned a year later. She traveled 200 thousand kilometers in one direction alone and set a mammal migration record that no one has yet broken, says Anastasia Kunitsa. Tourist attraction Nicknames for whales are also invented in other countries, but there is no single international system that would take into account the nicknames of all mammals. That is, they named the whale Valera in Russia, but if he migrated to Mexico, he could quite easily be nicknamed Miguel or Julio there. At the same time, there are separate international projects to study marine life. The most famous is HappyWhale. Tourists and travelers can upload to the site photographs of whales they have seen, along with a short description. The system processes the photo and sends information about whether anyone has seen this whale before. In the future, scientists will use this data to study populations of marine mammals. Travelers are also invited to become a guardian for the whale, give it a name and track its further movements on the website. To do this, you need to make a donation (the recommended amount, which is indicated on the website, is from 500 to 1000 dollars). Tourists also support research activities with funding. Fig.9: Tourists can upload photos of whales they see. Photo: screenshot from HappyWhale website - The project was invented by foreign scientists, but gradually our specialists joined it. In Russia, tourists most often manage to photograph humpback whales in the Far East. They love to show off their tails, which each have specific color patterns,” explains mammal specialist Anastasia Kunitsa. Fig.10: Humpback whales love to show tourists their tails. Photo: Kristinp Rau/HappyWhale In the Barents Sea, tour operators come up with names for whales to attract the attention of tourists. Thus, in Teriberka (a village in the Murmansk region), tour operators create their own whale catalogs. In local groups and chats, they periodically conduct voting among subscribers, and at the same time tell tourists about conscious observation of marine life and how not to harm them.

Fig.1: Two-week-old kittens of a domestic cat in the laboratory of the Chernogolovka Scientific Experimental Base This study tested the hypotheses that the discomfort calls of 2-week-old domestic cat kittens vary between individuals, contain sex cues, and may provide information to the mother about the physical health and potential of a given kitten to survive until the end of nursing. Body weight was also assessed as an indicator of the kittens' body condition. Since body weight depends on the size of the brood, the number of cubs in the brood was also taken into account. Additionally, since kittens' immunity may have been higher as a result of multiple paternity, this proxy for physical health was also considered in the study. The study was based on the idea that if it is not possible to raise an entire large litter, a mother cat could potentially redistribute resources in the form of milk, licking and warmth in favor of those kittens that have a higher chance of survival at the expense of those kittens that are weakened from diseases or physiological defects. We expected to find a relationship between the acoustic parameters of kitten calls and their subsequent survival to cessation of milk feeding, which could provide the mother with an honest indicator of the quality of the kitten's health and vitality. The cries of 57 two-week-old kittens were recorded during the blood collection procedure at the Chernogolovka Scientific Experimental Base. Of these, 53 kittens meowed, and 4 were silent. Of the 57 kittens, 47 survived to 90 days of age. However, the calls of kittens that survived and did not survive to 90 days of age did not differ in any acoustic parameter. Thus, the acoustic signs of sounds do not allow the mother to treat the kittens selectively, redistributing resources in favor of the stronger ones. Analysis of physical and acoustic parameters showed that the kitten's large body mass was the most important factor in its further survival and correlated with almost all acoustic parameters of calls. Litter size influenced body weight, with weight being highest in litters of 4 kittens, intermediate in litters of 5 kittens, and lowest in litters of 6–8 kittens. The presence of multiple paternity in the litter and the sex of the kitten did not affect body weight. Survival to 90 days was dependent on body weight. Body weight was lowest in kittens that did not survive to this age. Fig.2. Spectrograms show individual differences in the discomfort meows of 24 domestic cat kittens, 12 males (top two rows) and 12 females (bottom two rows). An audio file with sounds is available as Supplementary material for the article on the journal’s website. How can weaker kittens mask their low chances of survival by crying? Low-weight kittens increased their chances of survival by making calls that attracted increased attention from their mother. We found that the lower the kitten's body weight, the more frequent the calls, the longer the calls, the higher the energy quartiles, and the more calls contained nonlinear vocal phenomena. As has been shown previously for many mammalian species, such calls have increased attractiveness to adult caregivers of their young, and adults are less likely to ignore them. Fig.3. Comparison of observed and random variables attributing domestic cat kitten meows to a specific individual (a) and the correct sex (b). It was impossible to determine the sex of the kittens by their calls, and their identity could be determined with rather low accuracy. Interestingly, in another study, very clear differences between males and females were found in the meows of adult domestic cats at the Chernogolovka Scientific Experimental Base, while individuality was also low (Sedova et al., 2023, press release https://sev-in.ru/node/3323). The results of the study were published in the journal Behavioral Processes: Rutovskaya M.V., Volodin I.A., Naidenko S.V., Erofeeva M.N., Alekseeva G.S., Zhuravleva P.S., Volobueva K.A., Kim M.D., Volodina E.V., 2024. Relationship between acoustic traits of protesting cries of domestic kittens (Felis catus) and their individual chances for survival. Behavioural Processes, v. 216, 105009, https://doi.org/10.1016/j.beproc.2024.105009

Fig.1. Computational global optimization algorithms use the idea of random mutation and subsequent natural selection of the fittest species to improve the efficiency of the algorithm. Photo taken from https://hms.harvard.edu/news/origins-mutation Currently, computational algorithms for global stochastic (random) optimization and optimal control are widely used in the literature to solve various scientific and applied problems, including ecology and epidemiology. In particular, such algorithms are used in the development of optimal control of epidemics of infectious diseases in humans and farm animals. For example, one of the most important tasks is to minimize the number of infected organisms after a fixed amount of time with limited financial resources to solve the problem. Note that global optimization methods differ from local ones in that a global one is sought, i.e. biggest maximum. However, the computational methods of global optimization existing in the literature, in particular those using stochastic algorithms, have an important drawback. Mathematically, in high-dimensional spaces, the convergence of the solution to the global maximum is not guaranteed, i.e. there is a possibility of getting “stuck” in some local maximum, which is a gross error of the algorithm. In this case, optimal control of the system is impossible. This paper proposes a unique approach to the development of global optimization methods based on the classical Darwinian idea of evolutionary selection, in particular, the work uses the principle of survival of the fittest species in the presence of competition from other species. The mathematical optimization method constructed in the work (generation of random mutations followed by selection of the fittest species) guarantees convergence, which is a problem for previously proposed methods, which are known in the literature as “nature-like” methods. The convergence of the proposed optimization algorithm is mathematically rigorously proven. The proposed algorithm is also compared with previous algorithms in its class and its high efficiency is shown. An important role in the effectiveness of the new algorithm is played by modeling the process of random mutations, for which the anisotropy effect is introduced (in a hypothetical multi-dimensional parameter space, mutations occur differently in different dimensions). Next, the proposed algorithm is used to construct a strategy for optimal control of an epidemic in a population consisting of interacting groups (agents) with different characteristics, such as infectivity, frequency of contacts with other groups, etc. In the considered model, optimal control of the epidemic is carried out under restrictions on program funding implementation of control. The work was published in the journal Communications in Nonlinear Science and Numerical Simulation. Kuzenkov, Oleg A., Andrew Yu Morozov, and Samvel A. Nalchajyan. "Revisiting ‘survival of the fittest’principle in global stochastic optimisation: Incorporating anisotropic mutations." Communications in Nonlinear Science and Numerical Simulation 130 (2024): 107768. https://doi.org/10.1016/j.cnsns.2023.107768

Fig. 1. Location of points of ship scientific observations in 1977-2021, used in the analysis of the distribution of sharks in Russian Far Eastern waters (numbers indicate geographical references: seas, islands, bays, capes, etc.). Sharks play an important role in marine ecosystems. As predators of the highest trophic level, they not only represent a link in the food chain through which energy and organic matter are transferred from lower to higher trophic levels, but also consume large quantities of commercial species of invertebrates and fish. Many shark species are of commercial importance. There are about 30 species of sharks found in the North Pacific Ocean, including Russian Far Eastern waters. Among them, five species are the most common: the blue shark Prionace glauca, the shortfin mako shark Isurus oxyrinchus, the salmon shark Lamna ditropis, the Pacific spiny dogfish Squalus suckleyi and the Pacific sleeper shark Somniosus pacificus. The first two inhabit the warm ocean waters of all oceans, and the last three live only in the Northern Pacific. Employees of the A.N. Severtsov Institute of Ecology and Evolution RAS and the P.P. Shirshov Institute of Oceanology RAS analyzed long-term data for the last 40-plus years (since 1977) on the captures of the five most common species of sharks in Russian Far Eastern waters. The analysis was based on the results of scientific ship observations, which included about 69 thousand trawl stations from the sea surface to a depth of about 2 km (Fig. 1). The purpose of the study was to understand how the distribution boundaries and abundance of sharks in the specified area changed over time. It was found that the widest distribution and maximum catches of salmon and blue sharks were observed in the 1980s. Spiny dogfish was most widespread in the 2000s, with maximum catches recorded in the 1980s and 2010s. The sleeper shark was most widely distributed in the 1980s, with maximum catches occurring in the 2000s. The mako shark was only recorded in our waters in the 1980s and 2010s. The distribution boundaries of different shark species showed different dynamics during the study period. Significant changes in the spatial distribution and position of distribution boundaries are due to both subjective reasons and climatic changes. The results obtained provide an opportunity to determine and predict the locations of shark aggregations in Russian Far Eastern waters, which may be of practical importance. The Pacific dogfish is fished in Japan, the USA and Canada, but is not caught in Russian waters, although the opportunity is present. The sleeper shark getting into pollock trawls in large quantities (Fig. 2) greatly complicates fishing. Information about areas of its significant concentrations may be useful to fishermen from the point of view of avoiding such places. The mako shark can pose a direct threat to humans (cases of its attacks on people are well known, including in the Far East). Therefore, knowledge about the patterns of its distribution is of particular value. Article imprint: Orlov, A.M., Volvenko, I.V. (2024). Uninvited guests and permanent residents: long-term changes in the distribution and abundance of the five most common sharks in the northwestern Pacific. Reviews in Fish Biology and Fisheries. https://doi.org/10.1007/s11160-024-09834-6 Fig. 2. Catch of sleeper sharks in the western part of the Bering Sea on one of the research vessels (author O.A. Mishanova, Pacific branch of VNIRO - TINRO, Vladivostok). Related materials: Fishery: "Science has identified the most shark-rich places in the Far East" Fishnews: “Science has identified the most shark-rich places in the Far East”

One of the model species for studying microevolutionary issues is a small insectivorous mammal - the common shrew Sorex araneus Linnaeus 1758, which lives in Northern Eurasia from the British Isles to Yakutia. This species is notable primarily for its unusual sex determination system, namely the presence of a sexual trivalent in males (XY1Y2). Moreover, among all shrews, it is S. araneus that is characterized by amazing karyotype variability - at least 76 intraspecific chromosomal races, differing in the structure of karyotypes, have been described to date. The races are distributed parapatrically and, at areas of contact, form hybrid zones, the width of which is inversely proportional to the degree of differences in karyotypes. Of the 36 hybrid zones studied, the most interesting was the zone between the “Moscow” and “Seliger” races on Valdai, since these races are characterized by maximum karyotypic differences and in meiosis, natural F1 hybrids form the longest currently known configuration - a multivalent of 11 chromosomes (CXI). Fig.1. (A) G-stained karyotype of a hybrid male F1 between the “Moscow” and “Seliger” chromosomal races of the common shrew Sorex araneus; (B) 11-chromosome multivalent g/gm/mq/qp/pr/rk/ki/ih/hn/no/o, CXI, at diakinesis/metaphase II stage of meiosis. Chromosome arms are designated according to the nomenclature of the standard S. araneus karyotype (Searle et al., 1991). It was assumed that such multivalents could disrupt the course of meiosis, and as a result, hybrids would either suffer from reduced fertility or be completely sterile. And, therefore, gene flow in such hybrid zones should be sharply limited. A team of authors from the Institute of Ecology and Evolution of the Russian Academy of Sciences (S.V. Pavlova and N.A. Shchipanov) and IOGEN RAS (S.N. Matveevsky and O.L. Kolomiets) for the first time used an expanded set of modern cytogenetic and immunocytochemical methods, and also used electron microscopy for analysis of karyotypes and the course of meiotic divisions in pachytene spermatocytes in natural maximally karyotypically “complex” F1 hybrid males between the “Moscow” and “Seliger” races, carrying the CXI-multivalent. Fig. 2. Immunostained pachytene chromosomes in spermatocytes of the F1 hybrid between the “Moscow” and “Seliger” races and the scheme of the CXI multivalent: the color of each chromosome arm corresponds to the karyotype scheme in the upper part of the figure. Scale – 5 μm. It turned out that despite the minimal proportion of anomalies found in spermatocytes, such as chromosome associations, stretched centromeres and the absence of recombination nodes in some chromosomal arms of the CXI multivalent, F1 hybrids have a large number of morphologically normal active sperm. All other studied meiotic patterns also did not differ significantly from those in individuals of “pure” races. Thus, the study showed that the carriage of a whole set of structural chromosomal rearrangements does not lead to fatal sterility of F1 hybrid males, and therefore, the probability of free gene flow between parapatric chromosomal races of common shrews should be quite high. Fig. 3. Structure of spermatozoa in common shrews of the “Moscow” chromosomal race (A–E) and the F1 hybrid between the “Moscow” and “Seliger” races (F–K). Scale – 10 μm. However, the paradox is that the hybrid zone between the “Moscow” and “Seliger” races is one of the narrowest, only 1-2 km wide, and therefore the question of the mechanisms for maintaining the stability of the areas of hybridizing races remains open. The work was carried out with financial support from the Russian Science Foundation (grant № 22-24-00285, https://rscf.ru/project/22-24-00285/) (Q1) Matveevsky S.N., Kolomiets O.L., Shchipanov N.A., Pavlova S.V. 2024. Natural male hybrid common shrews with a very long chromosomal multivalent at meiosis appear not to be completely sterile // Journal of Experimental Zoology Part B: Molecular and Developmental Evolution, 342: 45–58. https://doi.org/10.1002/jez.b.23232

Fig.1: Life cycle of the fluke parasite Diplostomum pseudospathaceum. This trematode lives in fish-eating birds (their final host) in the form of sexually mature worms. The eggs pass through the feces into the water, where they develop into miracidia, free-swimming larvae that burrow into snails, the first intermediate host. There, miracidia reproduce asexually and the next larvae, cercariae, are released into the water. Next, the cercariae penetrate their second intermediate host - fish (rainbow trout) and develop there into metacercariae in the lens of the host's eye. Finally, flukes develop into adult worms when the fish is eaten by a piscivorous bird. Increasing population densities of ecologically and commercially important animal species is one of the main objectives of ecosystem management. This task is especially difficult in biotopes with a large number of parasites and predators. The creation of safe habitats with lower mortality rates has long been considered beneficial for increasing the survival of populations in commercial fish farming and in the recovery of endangered species. However, the presence of areas of the environment with low mortality can sometimes pose a danger to the survival of the population. In this study, a group of scientists, including employees of the A.N. Severtsov Institute of Ecology and Evolution RAS, revises the traditional concept of the positive role of shelters and addresses the role of behavior structuring (the ratio of “bold” and “timid” individuals) in the formation of population size in a hostile environment. A simple mathematical model was created in which organisms in a population use different tactics to defend themselves against natural enemies such as parasites and predators. The model predicts that although each refuge increases the survival rate of a particular organism, if there are not enough such areas, the overall mortality of the population will be higher. This effect is the result of the interaction of emerging dynamic behavioral structuring and strong intraspecific competition for safe zones. Non-plastic structuring of behavior reduces these negative effects. The work demonstrates the possibility of the emergence of non-plastic (stable) behavioral structuring: evolutionary branching of a monomorphic population, turning it into a dimorphic one, consisting of bold and timid individuals. The theoretical results are applicable to the optimization of breeding conditions in aquaculture of salmon fish infected with trematodes. Mathematical modeling is supplemented by experimental results on the infection of rainbow trout (Oncorhynchus mykiss) with different behavioral stereotypes by the trematode Diplostomum pseudospathaceum under different environmental heterogeneity. The results were published in the journal: Sandhu, S., Mikheev, V., Pasternak, A. Taskinen, J., Morozov A. Revisiting the role of behavior-mediated structuring in the survival of populations in hostile environments. Communications Biology 7, 93 (2024). https://doi.org/10.1038/s42003-023-05731-z

Figure 1. On Arteziana in the Stepnoy nature reserve. 2016 Photo by N.V. Kashinina The saiga antelope (S. tatarica) is a representative of the complex of large herbivorous mammals of the Pleistocene tundra-steppe ecosystem, and at the moment it is the only antelope that has survived in Europe to this day. Even in the last century it was a valuable commercial species. But in the early 1990s, due to a sharp decline in numbers, the problem of saiga conservation acquired global significance, and it was included in Appendix II of the Convention on International Trade in Species of Wild Fauna and Flora (CITES) and the Convention on the Conservation of Migratory Species of Wild Animals (CMS), as well as on the Red List of the International Union for Conservation of Nature (IUCN/МСОП) as a critically endangered species (Appendix II). Currently, there are five saiga populations in the world, and only one of them lives in Russia in the North-Western Caspian region in the “Black Lands” ecoregion, which includes the eastern regions of the Republic of Kalmykia and the southwestern regions of the Astrakhan region. The size of this population from the late 1990s to 2016, due to the influence of a complex of factors, including anthropogenic ones, decreased by more than 40 times. In addition, due to poaching, at that time there was a critical decrease in the proportion of adult males, i.e. the gender and age structure was disrupted. It is believed that due to a sharp decline in numbers, especially in “effective” numbers, genetic diversity may also decline, and therefore there has been a need to study this population. A group of employees from the Institute of Ecology and Evolution of the Russian Academy of Sciences conducted a study of 95 samples from saigas in the territory of the Black Earth Nature Reserve and the Stepnoy Nature Reserve. In order to determine whether the genetic diversity of saigas has decreased over the past 20 years, the samples were divided into two samples at different times - “Old” and “New”. Samples from the “Old” period were collected at the initial stage of population depression (at the end of the 20th century) and were stored in the collection of the Cabinet of Molecular Diagnostic Methods; samples from the “New” period were collected at a time of critically low numbers (3500 individuals in 2016). During the study, three types of molecular markers were analyzed: two selectively neutral (a fragment of the mtDNA control region and nDNA microsatellite loci) and one functionally significant (a fragment of the DRB3 gene of the Major Histocompatibility Complex, responsible for the body’s immune response), which made it possible to assess the genetic diversity of the population saigas of the North-Western Caspian region during the last depression in numbers. Figure 2. Process of collecting excrement for genetic analysis in 2016. As a result of the analysis of the data obtained for the saiga population of the North-Western Caspian region, a high level of diversity of the mtDNA control region was described (H = 0.92+/-0.02, π = 0.028+/-0.01), which was probably preserved from the ancestral population. Interestingly, the level of diversity of the MHC DRB3 gene, associated with resistance to extracellular parasites, was also high (Ho = 0.8; He = 0.78+/-0.05), which reflects the broad adaptive capacity of the studied population. However, the low heterozygosity rates and high inbreeding coefficient obtained for microsatellite loci (Ho = 0.422+/-0.08; He = 0.514+/-0.083, Fis = 0.181) are cause for concern. This may be due to significant selective elimination of male saiga antelopes. Currently, the most important task for preserving the saiga population of the North-Western Caspian region is to reduce androgenic influence, primarily in order to prevent poaching and habitat transformation. Figure 3. Median haplotype networks of the mtDNA control region (920 bp) Figure 4. Median networks of haplotypes of ten alleles of the DRB3 gene of the saiga population of the North-Western Caspian Sea (250 bp) The work was carried out with the support of the Russian Foundation for Basic Research grant No. 17-04-01351. Article published: Kashinina NV, Lushchekina AA, Sorokin PA, Tarasyan KK, Kholodova MV. (2023). The modern state of thе European saiga population (Saiga tatarica tatarica): mtDNA, DRB3 MHC gene, and microsatellite diversity // Integrative Zoology. 18. Pp. 661–676. https://doi.org/10.1111/1749-4877.12700

Mass extinction of saiga antelopes in a field in Kazakhstan. Photo taken from https://www.theguardian.com/environment/2018/feb/25/mass-mortality-events-animal-conservation-climate-change Predicting extinctions of populations of individual species and sudden changes in the functioning of an ecosystem has long been the focus of attention of ecologists and ecosystem management specialists. Mathematical modeling of environmental processes plays a key role in assessing the possibility of such events. Traditionally, in the scientific literature, modeling of population dynamics (in particular, predicting extinction of populations) has mainly focused on studying the dynamics of ecosystems in the long term, neglecting transitional regimes. Meanwhile, the environment is usually non-stationary, which may mean that long-term behavior is never observed in reality. Accordingly, the past two decades have seen a growing understanding and reconsideration of the role of transitional regimes in both empirical ecology and theoretical research, particularly in the context of species extinctions. Employees of the A.N. Severtsov Institute of Ecology and Evolution  RAS A.Yu. Morozov and colleagues consider several paradigmatic mathematical population models with discrete time of increasing complexity, such as one-species, two-species and three-species systems of interacting populations. A feature of the models under scrutiny is the consideration of spatial diffusion (movement) of organisms, which depends on population density. Mathematical modeling is used to study transient nonequilibrium processes to predict ecosystem viability and species conservation. The work shows that sudden collapse of an ecosystem and extinction of species can occur without any influence of external factors. This occurs as a consequence of the fact that a long transitional quasi-static regime is mistakenly taken for the final one, whereas at the end of this regime, the ecosystem abruptly switches to another regime without any external influence. Notably, delayed extinction can occur after thousands of generations of seemingly benign population dynamics. The study predicts that long-term transients are not only widespread in various models of population dynamics, but also have a wide variety of types of sudden collapse scenarios without changes in external environmental conditions. The predicted ubiquity of long-term transients underscores the need to incorporate them into species diversity conservation programs. The paper describes how such scenarios can be modeled and predicted. The results were published in the journal Biological Conservation (2024). AY Morozov, D Almutairi, SV Petrovskii, A Hastings. Regime shifts, extinctions and long transients in models of population dynamics with density-dependent dispersal. Biological Conservation, 2024, vol. 290, 110419, doi.org/10.1016/j.biocon.2023.110419