Fig. 1. Yellow steppe lemming (Eolagurus luteus) in the Moscow Zoo. Inbreeding is inevitable among animals in captivity. Its negative consequence is inbreeding depression, which manifests itself at the genetic and phenotypic levels. It is expressed in an increase in offspring mortality, a decrease in their fertility, growth and development rates, and a deterioration in immunity. In theoretical and practical terms, it is important to study the effect of inbreeding on the viability and reproductive performance of animals, particularly rodents. It is necessary to obtain accurate information on the gradual increase in the degree of inbreeding in artificial colonies of mammals and the accompanying changes in the above parameters, as well as to determine the level of inbreeding upon reaching which signs of inbreeding depression begin to appear. The yellow steppe lemming (Eolagurus luteus) is a rodent of the Arvicolinae subfamily of the Cricetidae family, inhabiting the deserts and semi-deserts of Eastern Kazakhstan, Mongolia, and Northwestern China. The modern range of the lemming is highly fragmented. Its sharp reduction occurred in the Late Pleistocene-Early Holocene due to climate change. Even before the mid-19th century, the species was common in the territory of modern Kazakhstan, but later became extinct in most of the territory, surviving only in the eastern part of the Zaysan Basin. Currently, the species is listed in the Red Book of the Republic of Kazakhstan. We assumed that the decline in numbers led to inbreeding, and therefore the lemmings surviving in the Zaysan Basin are inbred. Our small team decided that the special importance of studying the reproduction of yellow steppe lemmings in captivity is due to the fact that this is a rare species whose range has been steadily shrinking since the Pleistocene. And in order to understand how inbreeding can affect the future fate of this species, in artificial conditions it is necessary to estimate how the life expectancy of individuals will change, how many pairs of lemmings will reproduce and how many will not, whether the number of born and surviving young in a colony originating from only a few individuals will decrease with long-term inbreeding. Fig. 2. Changes in inbreeding coefficients of yellow lemmings from the Moscow Zoo colony depending on the breeding generation. The colony of yellow lemmings we studied was kept at the Moscow Zoo from 2017 to 2021 and originated from 10 individuals (5 females and 5 males), which in turn were the first-generation offspring obtained from 7 unrelated animals (3 females and 4 males) captured in the Zaysan Basin. Of the 10 founders of the colony, 5 animals (4 females and 1 male) were descended from the same mother. That is, the degree of inbreeding of individuals in each subsequent generation increased. We conducted a precise assessment of the effect of inbreeding on the lifespan and reproductive performance of lemmings by calculating the inbreeding coefficients of individuals. The animals belonged to the second to tenth breeding generations. The inbreeding coefficient (the probability of the presence of two homologous alleles of a gene that are identical in origin) was calculated for 177 individuals and varied from 0 to 0.29. The maximum values ​​(0.25-0.29) were recorded for individuals of the seventh to tenth generation. We also measured the lifespan (in days) of 61 animals and used information on reproduction or its absence in 45 pairs. For each pair that produced offspring, the total number of litters, offspring born and surviving to 30 days (the age of sexual maturity) was calculated. We found that the lifespan of the lemmings in the colony significantly decreased against the background of a progressive increase in their inbreeding coefficients. Statistical analysis also confirmed the negative impact of inbreeding on the main reproductive parameters, which depend primarily on the degree of inbreeding of females. In particular, the inbreeding coefficients of females that produced 10 or more (up to 23) broods varied from 0 to 0.14, and those of females that did not have offspring varied from 0.14 to 0.29. The negative impact of this factor increases if, in parallel with females, the degree of inbreeding of breeding males increases. In the colony, signs of inbreeding depression began to appear with an increase in the inbreeding coefficients of offspring to approximately 0.2 (starting from the sixth generation). Fig. 3. Decrease in the lifespan of yellow lemmings as their inbreeding coefficients increase. The study revealed the relative resistance of yellow lemmings to inbreeding depression in conditions where the artificial population is formed from only 7 animals. The yellow lemming in the Zaisan Basin is characterized by sharp fluctuations in numbers from mass reproduction to almost complete extinction due to unfavorable weather conditions. Apparently, the negative effect of inbreeding can neutralize the high reproductive potential. It can be assumed that in nature this allows this species to quickly restore its numbers after a period of decline. The results obtained can be used in developing a breeding program for this protected species in captivity. V.V. Streltsov, O.G. Ilchenko, E.V. Kotenkova The following article was published based on the results of the study: V.V. Streltsov, O.G. Ilchenko, E.V. Kotenkova “Long-term effect of inbreeding in the yellow steppe lemming (Eolagurus luteus) captive colony” // Current Zoology, 2024

Fig.1: Beaver pond Beavers are called ecosystem engineers because they rebuild aquatic ecosystems and have a significant impact on many aquatic and near-aquatic organisms. Mostly, beavers are widely known for their ability to build dams and create ponds. However, their activity is mainly manifested in small streams, while beavers also live in lakes, small reservoirs, swamps, and large rivers, where they are almost never engaged in construction. But wherever they live, they always dig - holes to live in, and canals to move and carry branches and logs. It is the digging activity of beavers that is their main impact on nature, so it would be fairer to call beavers diggers rather than builders. Fig.2: A floodplain reservoir at the beginning of summer. From above, underwater beaver canals connecting burrows are clearly visible. The rest of the space is overgrown with vegetation, and by autumn, water will remain only in the areas of the reservoir deepened by beavers. One of the main places where beavers live are floodplain reservoirs – numerous and very diverse water bodies that are filled with river waters during the flood. Now, due to global climate change, rivers have become less flooded, so many floodplain reservoirs do not receive water in the spring, and gradually dry up and become overgrown. This forces beavers to adapt to new conditions in order to preserve their habitats. Fig.3: The reservoir has almost completely dried up and become overgrown; water remains only in the depressions in the area of ​​old beaver burrows. A group of researchers from the Severtsov Institute of Ecology and Evolution of the Russian Academy of Sciences, the Geography Department of the Lomonosov Moscow State University, and the Privolzhskaya Lesostepye Nature Reserve assessed the scale of the impact of beaver burrowing on floodplain water bodies. To do this, a map of all floodplain water bodies in the upper reaches of the Khoper River (within the Penza Region) was compiled, 36 of which were surveyed during field expeditions, and 46 remotely using GIS analysis. The study revealed a significant impact of beavers on small floodplain water bodies. Due to the appearance of numerous burrows and channels, the total area of ​​water bodies increased by 40%, and the perimeter by 60%. Due to the burrowing activity of beavers, the coastline became more winding, which completely changed the structure of coastal habitats in 60% of water bodies. Fig.4: The reservoir persists only due to active deepening; the soil that beavers rake from the bottom to the edge of the channel is clearly visible. Approximately a third of the reservoirs were significantly transformed by the activity of beavers, and every tenth reservoir existed exclusively within the canals dug by beavers, representing "beaver digs". If not for the activity of this animal, such reservoirs would dry up completely by the end of summer. At the same time, it was proven that the number and length of beaver holes and channels depended on the amplitude of changes in the area of ​​reservoirs. The more the reservoir dried up, the more actively beavers dug there, trying to deepen and prolong its life, mitigating the negative effects of climate change. Fig.5: Beaver canals, which connect drying up reservoirs, help many aquatic organisms to survive during periods of low water. Beaver canals and burrows serve as important habitats for aquatic organisms, they are used as homes and shelters, serve for movement between water bodies and convenient exit to land. Active burrowing activity prevents the capture of water bodies by semi-submerged plants, thus slowing down their overgrowing and subsequent drying. Changes in the bottom relief by beavers form a mosaic of habitats, which contributes to an increase in biodiversity. Unfortunately, if problems with spring floods continue, many water bodies will become unsuitable for beavers, no matter how hard they try to deepen them, and this will negatively affect the aquatic fauna and flora of the floodplains. However, the burrowing activity of beavers can become an example of possible nature-oriented strategies for the conservation and restoration of small floodplain water bodies. The work was published in the journal Limnologica: Volume 109, November 2024, 126214 Ecosystem engineering at the regional scale—Beaver impact on floodplain pondscapes. The study was carried out within the framework of the RSF project 23-24-00018.

The Caspian seal is endemic to the Caspian Sea. Over the past century, the seal population has significantly decreased, and the species is currently listed in the Red Book of the Russian Federation. Many factors adversely affect the state of the species, including the reduction of ice cover, habitat transformation, reduction of the food supply, animal capture, shipping, invasive species, etc. Pollution of the habitat also has a negative effect on marine mammals. The staff of the IEE RAS, together with the I.D. Papanin Institute of Biology of Inland Waters (IBW RAS) and the Kazakhstan Agency of Applied Ecology (KAAE), checked the work on assessing the content of total mercury in the fur, vibrissae, and blood of Caspian seals. The assessment was carried out for live and dead (found dead) individuals of the Caspian seal, living in the northeast of the Caspian Sea (in the waters of the Republic of Kazakhstan) in the fall. On average, the seal fur contained 2604 ± 1708 μg/kg mercury (n = 64), with a range of 258 to 8511 mg/kg. In the whiskers, the average mercury content was 3412 ± 1804 μg/kg mercury (n = 59), with a range of 984 to 12957 μg/kg. In the blood, the average mercury content was 114 ± 68 μg/L mercury (n = 59), with a range of 88 to 350 μg/L mercury. These concentrations are generally comparable with studies of other pinniped species. No sex differences were found in the mercury content of the fur, whiskers, or blood. Age differences were found only in the analysis of fur: individuals aged 3+ years contained significantly more mercury than individuals aged 0-2 years. In four of the studied individuals, the concentration of mercury in the fur exceeded the threshold values, which in other studies led to disturbances in the nervous system (>5400 μg/kg). However, in most of the studied animals, the detected mercury concentrations were below the values ​​at which the effect on the body was recorded in other species of marine mammals. The work was carried out with the financial support of North Caspian Operating Company N.V. and Kazakhstan Agency of Applied Ecology LLP. The authors express their gratitude to the management of the above-mentioned companies. The work was published in the journal Marine Pollution Bulletin (Q1, IF = 5.3), Total mercury in fur, whiskers and whole blood of Caspian seals (Pusa capsica) from north-east of Caspian Sea (Kazakhstan).

The round table "Decarbonization Technologies", organized by the Center for Decarbonization Technologies of USPTU, was held on October 25 at the "Boiling Point - Ufa" of the Interuniversity Campus of the Eurasian World-Class Scientific and Educational Center. The presentations covering current topics in the field of climate change studies were listened to with great interest by students and staff of USPTU, Ufa Federal Research Center of the Russian Academy of Sciences and Ufa University of Science and Technology. Head of the V.N. Sukachev Laboratory of Biogeocenology at the Institute of Ecology and Evolution of the Russian Academy of Sciences Yulia Kurbatova presented a report on instrumental methods for observing greenhouse gas flows, in particular, she spoke about the theoretical foundations, instrumentation and methodology for organizing field observations. The methods of turbulent pulsations in environmental studies, the Russian network for monitoring pools and flows of climate-active substances, as well as international experience in organizing instrumental observations of greenhouse gases in terrestrial ecosystems were considered. Trofim Maksimov, Doctor of Biological Sciences, Deputy Director General for Science and International Projects of the Federal Research Center "Yakutsk Scientific Center of the Siberian Branch of the Russian Academy of Sciences", spoke about representative ecosystems of Russia in the context of climate change. He paid attention to the topic of the impact of global warming and anthropogenic load on northeastern Eurasia in the late 20th - early 21st centuries, noting the importance of monitoring cryolithozone ecosystems. The roundtable participants actively discussed the reports, asked questions to the speakers and shared their opinions. *The roundtable was held as part of the implementation of the strategic project "Decarbonization Technologies" of the Priority-2030 program.

Fig.1: New species Ornithophila baikalica. A - General view from the back, B - General view from the ventral side, C - Thorax and head, D - Head, E - Abdomen. Blood-sucking flies of the Hippoboscidae family are distributed throughout the world. This family of parasites of birds and mammals currently includes more than 200 species. These insects are of great veterinary importance as carriers of dangerous diseases and other groups of parasites. The genus Ornithophila is one of the smallest genera among Hippoboscidae. Currently, it includes only two species: Ornithophila gestroi and O. metallica. These species are holoptera, widely specialized parasites of birds living in the tropics and subtropics of Asia, Africa, Europe and Central Asia, including Russia and Kazakhstan. During the annual ringing of birds in the Baikal State Nature Reserve, a new species was collected and described - Ornithophila baikalica. This species was found on the thick-billed warbler, a bird that breeds in southern Siberia and the Russian Far East and migrates in winter to Southeast Asia and occasionally to Egypt, Bhutan, Japan and Malaysia. The new species differs from all known species of the genus in that tergites 3–5 of the female abdomen are reduced to the size of dots. The work was published in the journal Nature Conservation Research 9(2): 100–104: A new Ornithophila (Diptera: Hippoboscidae) species from Baikal State Nature Reserve (Russia).

Figure 1. Head and neck dimensions in several studied herbivorous mammals. In a new article published in the Journal of Anatomy, Ruslan Belyaev and Natalia Prilepskaya, employees of the Laboratory of Ecology, Physiology, and Functional Morphology of Higher Vertebrates at the Institute of Ecology and Evolution of the Russian Academy of Sciences, together with colleagues from Yakutia, Israel, and Belgium, conducted a large-scale study of body proportions in large herbivorous mammals. The work examined dozens of skeletons of modern elephants, even-toed and odd-toed ungulates, as well as some fossil representatives of these orders, including woolly and steppe mammoths, the American mastodon, megabelodon, hyrachyus, etc. Comparison of modern odd-toed ungulates (horses, rhinoceroses, tapirs) and elephants with their Paleogene ancestors made it possible to demonstrate how the body plan changed in these phylogenetic lines over tens of millions of years of evolution, and to offer biomechanical interpretations of the observed changes. The Cenozoic is rightfully considered the era of mammals. After the Cretaceous-Paleogene extinction, mammals became full-fledged masters of the planet, occupying many ecological niches previously inaccessible to them. In many phylogenetic lines, large and gigantic forms appeared, some of which exist today. The appearance of large herbivorous mammals is extremely diverse, the differences in the body proportions of elephants and giraffes, horses and rhinoceroses, bison and hippos make their exterior instantly recognizable to our eyes. However, in addition to the striking differences, these animals also have numerous similarities in the biomechanics of their bodies, which were formed in response to the adaptation of the musculoskeletal system to gigantism. The earliest known ancestors of proboscideans and odd-toed ungulates were quite small forms. Thus, the oldest known proboscidean – Eritherium azzouzorum from the Paleocene (~60 million years) of Morocco – was slightly larger than the hyrax and weighed 5-6 kg. The fairly well-known plesiomorphic odd-toed ungulates from the early Eocene (50-55 million years) of North America and Eurasia were the size of a dog and weighed from 9-10 to 20-50 kg. How have modern elephants, horses and rhinoceroses changed compared to their Paleogene ancestors, apart from an impressive increase in size? In both orders, changes occurred in the course of evolution associated with both allometric growth and deep specialization of the locomotor apparatus. Moreover, if allometric changes turn out to be, in many ways, similar to each other, then the directions of specialization of the locomotor apparatus in elephants and ungulates turn out to be directly opposite. Figure 2. Relative height of the forelimb in large herbivorous mammals: (a) giraffe, (b) moeritherium (late Eocene of Africa), (c) Indian elephant, (d) arsinoitherium (late Eocene of Africa), (e) two-humped camel, (f) arenahippus (early Eocene of North America), (g) kulan, (h) bison, (i) Indian rhinoceros, (j) hippopotamus. In the case of elephants, the musculoskeletal system specializes in an extremely economical mode of locomotion based on the inverse pendulum principle. Surprisingly, this principle is also implemented in human bipedal locomotion. In the course of evolution, proboscideans lose not only the ability to jump and use asymmetric gaits, including gallop, but also the ability to run as such. Even during the fastest locomotion, one of the elephant's limbs always maintains support on the substrate. Along with the loss of the ability to use a gallop, proboscideans almost completely lost the ability of the back to bend in the sagittal plane, their hind limbs lost their three-link structure (thigh, shin, foot) becoming two-link, the joints of the limbs straightened, which made the leg columnar (Figure 2). Such a columnar limb turns into a kind of pole, allowing for a highly efficient transition of the kinetic energy of the moving center of mass into potential and vice versa. At the same time, energy during locomotion is practically not spent on vertical movements of the center of mass, which in elephants during fast movement is 7 times lower than, for example, in a tapir. As a result, elephant walking using the inverted pendulum principle is one of the most energy-efficient ways of movement among terrestrial vertebrates. During evolution, the increase in the body size of proboscideans is accompanied by a significant increase in the height of their forelimbs and hindlimbs. Thus, compared to the Moeritherium from the late Eocene of Africa (El Fayoum, Egypt), the height of the limb of modern elephants relative to their own body length increases more than twice (Figure 2b, c). This allows them to increase the stride length (and, as a consequence, the speed of movement) and simultaneously reduce vertical oscillations of the center of mass during locomotion. The elongation of the limbs occurs due to the length of their proximal segments (scapula, shoulder and forearm in the forelimb, thigh and lower leg in the hind limb), while the contribution of the hand and foot to the limb length becomes minimal. Long limbs were also characteristic of some groups of extinct proboscideans, including mastodons and amebelodons. However, the longest limbs among the studied proboscideans were possessed by mammoths – Mammuthus primigenius and M. trogontherii. The taller pendulums of the limbs would have provided even more energy-efficient locomotion than modern elephants, making the limbs ideal for long seasonal migrations and overcoming land and water obstacles. In ungulate mammals, the exact opposite optimization of the locomotor apparatus occurs. If proboscideans lose the ability to run, then ungulates, on the contrary, become one of the most specialized in running. They retain the three-link structure of the limbs, characteristic of plesiomorphic therian mammals, and their joints remain visually “bent” when compared with the practically straight limbs of elephants. Three-link limbs, the joints of which are oriented in a zigzag manner, allow ungulates to optimize the kinematics of the joints and reduce energy costs for undesirable mechanical work of muscles directed against each other inside the limb. This significantly reduces energy costs when running, especially with the use of asymmetric gaits. During the evolution of odd-toed ungulates, there is a significant reorganization of the locomotor apparatus, which is most obvious in horses. The relative height of the limbs in these animals becomes significantly greater than that of their small Paleogene ancestors (Figure 2e, g). Moreover, unlike elephants, the increase in height occurs primarily due to the lengthening of the distal segments, i.e. the hand and foot. Their length in equines increases almost twice as much as in their Paleogene ancestors. Such elongation of the limbs allows the bulk of the muscles to be shifted proximally, making the lower half of the leg relatively lighter. This reduces the expenditure of mechanical energy, reduces the moment of inertia of the limb and increases the speed of its transfer during running. Along with the increase in the absolute and relative length of the limbs, equines experience a twofold increase in the relative length of the neck and a one and a half fold increase in the relative length of the skull. A significantly longer neck and head allow horses to retain the ability to graze at the level of the substrate despite the significantly increased height of the legs. The work is published in the journal: Ruslan I. Belyaev, Gennady G. Boeskorov, Alexander N. Kuznetsov, Mathys Rotonda, Natalya E. Prilepskaya. 2024. Comparative study of the body proportions in Elephantidae and other large herbivorous mammals. Journal of Anatomy.

Fig. 1. The route of the R/V Professor Levanidov in the Siberian Arctic seas in 2019 (top left), trawl stations (triangles), including those where Lycodes spp. were caught (circles) in the Laptev (top right), Chukchi (bottom left), East Siberian (bottom center) and Kara (bottom right) seas. Despite the growing interest in Arctic biota in recent decades, there are many gaps in our knowledge of the composition and distribution of species, including the Arctic ichthyofauna. One of the poorly studied groups is the Lycodes genus, which belongs to the widespread, numerous and species-rich Zoarcidae family in the Arctic. At least 34 species of this family have been recorded here, which is about 17% of the total species diversity of fish. Of these, about 70% are representatives of the Lycodes genus. These bottom dwellers of the shelf and continental slope play an important role in food chains, ensuring the transfer of organic matter and energy from bottom organisms to higher trophic levels (large predatory fish and marine mammals). Some Lycodes can reach a length of more than 50 cm and are considered suitable as food products, but their bycatch is currently not used, since they do not form dense clusters. The species composition and actual ranges of some Arctic lycodids still remain controversial due to insufficient study and often incorrect species identification. Fig. 2. Different color variations of the seminude lycodes Lycodes seminudus (scale 1 cm). The staff of the Zoological Institute, the Institute of Oceanology and the A.N. Severtsov Institute of Ecology and Evolution of the Russian Academy of Sciences analyzed and summarized the materials on 12 species of lycodes collected during the expedition of the R/V Professor Levanidov in 2019 in four seas of the Siberian Arctic (Chukchi, East Siberian, Laptev and Kara). The morphological features and their variability, as well as the distribution of these species, are described and discussed. L.reticulatus was first discovered in the East Siberian Sea, L.pallidus in the Chukchi Sea, L. raridens in the Laptev Sea and L.rossi in the Chukchi and East Siberian Seas. Fig. 3. The most morphologically variable in the Arctic is the pale lycodes Lycodes pallidus (scale 1 cm). The obtained data significantly expand our knowledge of the modern ranges of Arctic ichthyofauna and may indicate the expansion of Pacific species into the Arctic. They also show that L. pallidus and L. polaris are probably the most numerous and widespread species in the three seas of the Siberian Arctic. Moreover, the first species is characterized by the widest range of morphological variability. The presented data are valuable for monitoring the biodiversity of Arctic ecosystems, which are subject to rapid transformation in the context of climate change and increasing anthropogenic pressure. Published data of the article: Nazarkin M.V., Orlov A.M. 2024. Extending the knowledge of taxonomy, biodiversity, and biogeography of Arctic ichthyofauna: A case study of the most diverse genus Lycodes (Zoarcidae) // Zoologischer Anzeiger. V. 313. P. 355-365. https://doi.org/10.1016/j.jcz.2024.11.003

Fig.1: Varvara at work We are happy to share a joyful event with you. This year, Varvara Krolenko, a true master of making sections of biological objects, entered the graduate school of Alexey Alekseevich Kotov. Under the program for updating the equipment base of organizations of the Ministry of Science and Higher Education of the Russian Federation, the institute purchased a Leica EM UC7 ultratome and today, with joint efforts, we launched it. The device is designed to obtain semi-thin and ultra-thin sections of objects embedded in epoxy resins. Varya will use it to cut water fleas (Crustacea: Cladocera) for her PhD dissertation. Fig.2: B - first sections on the water surface After sectioning, Varvara examines the sections using a transmission electron microscope and, based on the data obtained, will perform volumetric reconstructions of the organ systems of cladocerans. The appearance of such a device at the institute opens the way to research that is at the forefront of science. Example. Fig.3: a ready line of sections But sectioning biological objects is only one of the preparatory stages for conducting ultrastructural studies. In order to fully perform such work in our institute, it is necessary to purchase a transmission electron microscope, as well as equip a separate room for sample preparation. Now in the room where the ultratome is registered, 4 people, 3 direct microscopes, 4 stereomicroscopes and many other valuable things fit on 18 square meters. In addition, schoolchildren and students from other organizations come to visit us on a regular basis. We all have very different tasks, from routine faunistics and floristry to boring taxonomy and even work with living objects. Expanding the list of laboratory topics, we also dream of increasing the areas for work. And we definitely have enough imagination and strength to master and equip them.

Fig 1. Daphnia atkinsoni. Source: Pereboev et al. / Zoologica Scripta, 2024. Biologists have found that two species of crustaceans called water fleas — Daphnia atkinsoni and Daphnia triquetra — independently acquired a crown-of-thorns-like structure on their heads during the course of evolution. This crown helps them protect themselves from predators, and therefore increases the crustaceans’ chances of survival. Genome analysis has shown that the “crown of thorns” is a very ancient acquisition that arose in daphnia as early as the Mesozoic era (roughly estimated at 145–66 million years ago). The data obtained help to better understand how protective adaptations evolved in invertebrates. The results of the study, supported by a grant from the Presidential Program of the Russian Science Foundation (RSF), were published in the journal Zoologica Scripta. Fig 2. Daphnia atkinsoni head with a crown of thorns, top view. Photographed with a confocal laser microscope. Source: Alexey Kotov. Daphnia, also known as water fleas, are crustaceans that inhabit most continental bodies of water in the world. They serve as food for small fish and other vertebrates and invertebrates. As early as the 18th century, scientists discovered that some species of daphnia have special adaptations to protect themselves from predators, such as shield shrimp (Notostraca). These include a tail spine, a hard chitinous plate on the head, and surrounding spines. The spines around the head plate of daphnia resemble a crown, which is why biologists call such structures a "crown of thorns." The "crown" is not permanent - it can form in crustaceans when predators are present in a body of water, and be lost when there is no danger. Until now, it remained unknown whether the "crown of thorns" in daphnia arose once in the process of evolution, or whether different species acquired it independently of each other. Biologists from the A.N. Severtsov Institute of Ecology and Evolution of the Russian Academy of Sciences (Moscow), in collaboration with colleagues from other institutes, studied two species of daphnia capable of forming a "crown of thorns" - Daphnia atkinsoni and Daphnia triquetra. The scientists isolated DNA from crustaceans previously caught in reservoirs in the south of Russia, Mongolia and Kazakhstan. The researchers decoded the obtained genetic sequences and compared them with the genomes of daphnia that do not have a similar protective structure on their heads. Genomic analysis showed that Daphnia atkinsoni and Daphnia triquetra are two genetically independent lineages, each of which has close relatives among species without a "crown of thorns". Thus, Daphnia atkinsoni turned out to be related to the "crownless" species Daphnia tibetana, and Daphnia triquetra to the species Daphnia studeri. In addition, the authors determined that the group of species that includes Daphnia atkinsoni and Daphnia triquetra arose in the late Mesozoic - approximately 145-66 million years ago. Accordingly, the appearance of the "crown of thorns" in daphnia as a means of protection from predators, which have existed for just as long, is just as ancient. "The data we have obtained allows us to better understand the history of the emergence of protective adaptations in freshwater animals during the course of evolution. It is the cladocerans that serve as model objects for such studies. Structures similar to the "crown of thorns" increase the chances of survival in the presence of natural enemies, and are therefore important in terms of maintaining the species. In the future, we plan to continue studying the crustaceans Daphnia atkinsoni, since there is evidence that this name hides a whole group of related species. We want not only to clarify the number of species in the group, but also to understand how they differ in the regulation of the appearance and disappearance of the "crown of thorns" in the presence or absence of a predator in the reservoir," says Alexey Kotov, a participant in the project supported by a grant from the Russian Science Foundation, Corresponding Member of the Russian Academy of Sciences, Professor of the Russian Academy of Sciences, Chief Researcher of the Laboratory of Ecology of Aquatic Communities and Invasions of the A.N. Severtsov Institute of Ecology and Evolution of the Russian Academy of Sciences. The study involved staff from the Papanin Institute of Inland Water Biology of the Russian Academy of Sciences (Borok), the Koltsov Institute of Developmental Biology of the Russian Academy of Sciences (Moscow), and Charles University (Czech Republic). Related materials: Indicator: "Two species of water fleas have put on "crowns of thorns" in the process of evolution independently of each other" Naked Science: "Two species of water fleas have put on "crowns of thorns" in the process of evolution independently of each other" Rambler: "Two species of water fleas have put on "crowns of thorns" in the process of evolution independently of each other"

During the years of depression in the rodent population, colonies of Mongolian gerbils look lifeless, since the animals almost never appear on the surface, and their alarm cries cannot be heard by humans, since they are emitted in the ultrasonic range, significantly exceeding the upper threshold of human hearing sensitivity. Researchers from Lomonosov Moscow State University, the Institute of Natural Resources of the Russian Academy of Sciences, the Moscow Zoo, and the A.N. Severtsov Institute of Ecology and Evolution of the Russian Academy of Sciences studied the acoustic structure of ultrasonic alarm calls of Mongolian gerbils Meriones unguiculatus. The studies were conducted in the natural conditions of the Daurian Steppe. To verify the obtained recordings, the acoustic parameters of the ultrasounds of wild gerbils were compared with alarm calls recorded in family groups of Mongolian gerbils in captivity during simulated cage cleaning. In mid-summer 2021, when the data for this study were collected, the population density of the Mongolian gerbil and all other common rodent species in the Daurian Steppe was very low due to heavy snowfall in May, which flooded the burrows with breeding animals. As a result, in June and July there were many freshly dug burrows that looked inhabited, but live gerbils were seen only three times during 17 days of constant visits to the colonies. The ultrasonic calls were monitored using an Echo Meter Touch 2 PRO smartphone attachment, recording range from 6 kHz to 128 kHz. This attachment allows viewing the ultrasound spectrogram in real time. However, such a spectrogram is clearly visible when recording bat calls at night, and is not visible in the bright sun during the day, when Mongolian gerbils are active. Therefore, the recording was done blindly and then the recorded ultrasounds were immediately viewed on a computer. Two researchers regularly visited potentially inhabited gerbil colonies and conducted one recording session of 10-30 min per visit. The researcher stood or slowly moved along the entrances to the burrows, directing the recorder at the burrow openings. All ultrasonic alarm calls were recorded from burrows; animals on the surface did not emit any calls. The presence of species-specific ultrasounds indicated that the burrow was inhabited on the day of recording. This approach can be used to search for inhabited burrows of Mongolian gerbils in conditions of severe population depression, when visual observations are ineffective. In both the wild and captive conditions, the ultrasonic alarm calls of Mongolian gerbils were drawn-out ultrasounds with an average duration of 118 milliseconds, a flat fundamental frequency contour, and an average maximum fundamental frequency of 26.84 kHz. It was found that alarm calls of Mongolian gerbils in captivity were somewhat shorter and higher in fundamental frequency, and followed each other with shortened intervals between calls compared to wild conditions. In addition to Mongolian gerbils, ultrasonic alarm calls are known only for three rodent species: the brown rat Rattus norvegicus, the Richardson's ground squirrel Spermophilus richardsonii, and the spotted ground squirrel S. suslicus. Mongolian gerbils also accompany their ultrasonic alarm calls with podophony: rhythmic paw strikes on the substrate in the frequency range audible to humans. However, podophony has only been observed and recorded in captivity. The evolutionary origin and adaptive use of the ultrasonic alarm call, which has poor penetrating ability both in burrows and above the soil surface, in a fairly large rodent remains unclear. The results of the study were published in the Q1 journal Mammalian Biology: Volodin I.A., Klenova A.V., Kirilyuk V.E., Ilchenko O.G., Volodina E.V., 2024. Ultrasonic alarm call of Mongolian gerbils (Meriones ungiuculatus) in the wild and in captivity: a potential tool for detecting inhabited colonies during population depression. Mammalian Biology, v. 104, p. 407-416.