In accordance with tradition, the IEE RAS employee who becomes the youngest Doctor of Science receives a challenge award - an eagle on a stand made of optical calcite (Iceland spar) from Nizhnyaya Tunguska. In December 2024, the award was received by Evgeny Vladislavovich Yesin, who defended his doctoral dissertation “Evolution of malmoid chars (Salvelinus malma complex, Salmonidae) of Kamchatka”. Before that, since 2021, the statuette was held by Alexey Sergeevich Opaev. We wish active work on doctoral dissertations to future winners of this award!

Fig. 1 (A) An infected pond snail secretes the dissemination stages of the parasite - cercariae (B), which penetrate the fish (C), damaging the lens (D). Cercariae of one line of the parasite are formed during asexual reproduction in the mollusk, and therefore are genetically identical to each other. The sexual process occurs in the intestine of a fish-eating bird (E). Eggs (F) fall into the water, where they hatch into a ciliated larva (G), capable of infecting the mollusk. The ability of parasite clones to infect the host and their growth rate influence the evolutionary success and virulence of the parasite (the harm caused to the host). In nature, the host is often infected by several clones simultaneously, and the interactions between them can determine the course of the infection. Researchers from the Severtsov Institute of Ecology and Evolution of the Russian Academy of Sciences (IEE RAS) have studied for the first time the relationships between parasite clones at different stages of infection development (at the time of infection and during the growth of larvae in the host). The scientists used the common trematode Diplostomum pseudospathaceum for this study. During its life cycle, this trematode consistently parasitizes pond snails, many species of freshwater fish and fish-eating birds, in whose intestines it completes its life cycle (Fig. 1). The scientists collected large pond snails infected with the trematode D. pseudospathaceum from natural reservoirs. Microsatellite analysis was then used to determine which of these harbored only one clone of the parasite, and these mollusks were used as a source of parasites in the experiment. Dolly Varden were infected with either individual clones or pairs of clones simultaneously. After several months, the fish were dissected, and the parasites found in their lenses were counted and measured (~4,000 parasites from 364 fish!). Fig. 2. (A) Infection rates of Dolly Varden with different clones of D. pseudospathaceum and a mixture of clones. (B) Infection rates of fish as a function of host size for different clones of the parasite. Note that the slopes of the lines differ, i.e. the clones differed in their ability to infect fish of different sizes. As expected, the parasite clones varied in their ability to infect fish (Fig. 2A) and growth rate in their eyes. Interestingly, the scientists found evidence of clone specialization for hosts of different sizes: some clones were more successful in infecting larger hosts, while others were not (Fig. 2B). This may be evolutionarily advantageous for the parasite, since it reduces intraspecific competition for host resources. Simultaneous infection of Dolly Varden with two clones led to three different scenarios: a) facilitated parasite penetration into the host; b) slowed down parasite growth; c) had no effect, compared to monoclonal infection. Thus, when the parasite clones interacted with each other (results of bootstrap analysis), they either cooperated during infection or competed during the larval growth stage. The most important conclusion of the work is that there is no universal answer to the question: “How will the parasite clones interact in the host organism?” It all depends on their combination. Such genotypic interactions can have a significant impact on the dynamics of infection and virulence of the parasite. The work was carried out by a team of authors from the Center of Parasitology of the IEE RAS (Mironova E.I., Spiridonov S.E., Sotnikov D.A., Savina K.A.), the Laboratory of Behavior of Lower Vertebrates of the IPEE RAS (Gopko M.V.) and the Russian State Agrarian University - Moscow Agricultural Academy (Sotnikov D.A., Shpagina A.A.) with the support of the grant of the Russian Science Foundation (23-24-00418). The article was published in the leading parasitological journal International Journal for Parasitology: Mironova, E., Spiridonov, S., Sotnikov, D., Shpagina, A., Savina, K., & Gopko, M. (2024). How do trematode clones differ by fitness-related traits and interact within a host?. International Journal for Parasitology.

Scientists from the Vitus Bering Kamchatka State University have discovered a population of the resident form of coho salmon in Lake Ostrovnoye on the southeastern coast of Kamchatka. When the Red Book of the region is reissued, the new population is planned to be included in the list of protected species, the university's press service reported. "This is the seventh known population of the freshwater form of this species on the peninsula. Unlike the usual migratory coho salmon, which migrates to the ocean, this fish constantly lives in fresh water. The resident coho salmon of Ostrovnoye leads a predatory lifestyle, preferring to feed on stickleback. The fish reaches sexual maturity in the fourth to fifth year of life. Scientists have established that spawning occurs in winter, and the population is quite numerous," the press service reported. According to the researchers, the lake basin is home to both resident and migratory forms of coho salmon. The migratory form swims up to the lake's tributary, the Bolotnaya River, to spawn, while the migratory fish spawn in the lake itself. There is reproductive isolation between the forms, although sometimes individual migratory spawners can swim to the lake's spawning grounds. Migratory and resident coho salmon are clearly distinguished in mixed catches. In September, spawning groups of both populations were at late stages of gonad maturity. Residential spawners weighing 180-250 grams are noticeably different from migratory fish, reaching 2-3 kg. It is noted that all previously known populations of migratory coho salmon in Kamchatka are included in the regional Red Book. They live in the lakes Kotelnoye, Khalaktyrskoye, Maloye Sarannoye, Golyginskoye, Ayaogytgyn and Kalanan. At the same time, the populations in Khalaktyrskoye and Kotelny are on the verge of extinction or have already disappeared due to overfishing. "When the Red Book of Kamchatka Krai is reissued, the new population of coho salmon is planned to be included in the list of protected species. Protection measures will be developed by the Ministry of Natural Resources of Kamchatka Krai. Experts are confident that it is necessary to inform the population that this is a rare, valuable fish that is better not to catch," the press service added. About Ostrovnoye Lake Lake Ostrovnoye, despite its proximity to Petropavlovsk-Kamchatsky, remained poorly studied for a long time. In September 2024, specialists from the Vitus Bering Kamchatka State University and the A. N. Severtsov Institute of Ecology and Evolution of the Russian Academy of Sciences conducted a comprehensive survey of the reservoir with an area of ​​4.3 square kilometers. The lake was formed as a result of block tectonics, typical for the southeastern coast of Kamchatka. The bottom of the reservoir is almost perfectly flat, with an average depth of 5 m. Depending on the altitude above sea level, such reservoirs can be either fresh or salty. Ostrovnoye is considered freshwater. "Residential populations of coho salmon occur in lakes rich in food, usually near the ocean coastline. There are few of them, and the problem is mainly that such populations are heavily overfished by amateur fishermen. Specifically, Lake Ostrovnoye had not been surveyed before, so no one knew about the local population of lake coho salmon," the press service quotes the words of the project leader, Doctor of Biological Sciences, employee of the Youth Laboratory of Anthropogenic Dynamics of Ecosystems of the Vitus Bering KamSU and the Laboratory of Ecology of Lower Vertebrates of the A. N. Severtsov Institute of Ecology and Evolution of the Russian Academy of Sciences, Evgeny Esin. During the research, the scientists also discovered that Lake Ostrovnoye has a high diversity of fish. Dolly Varden, char and a school of sockeye salmon live here. Residential nine-spined and three-spined sticklebacks live along the shore, the anadromous form enters the lake to spawn at the beginning of summer, and toothed smelt sometimes gets from the Ostrovnaya River. In autumn, starry flounder can be found here. The results of the study will be published in the journal "Problems of Ichthyology".

Figure 1. General appearance and natural habitats of Proasellus abini Marin & Sinelnikov, 2024: A – forest well, Sheeds, general view; B, C – individuals of the new species on the bottom and walls of the well; D, F – general dorsal view of a living individual of P. abini and its lateral view (e). The staff of the A.N. Severtsov Institute of Ecology and Evolution of the Russian Academy of Sciences (IEE RAS) described a new stygobiont species of the genus Proasellus Dudich, 1925 (Crustacea: Isopoda: Asellidae), Proasellus abini Marin & Sinelnikov, 2024, which inhabits hypogeum biotopes and underground waters of the Abin River basin, located in the southwestern foothills of the Caucasus Range. At present, only one species of this genus, Proasellus linearis Birštein, 1967, is known from the western foothills of the Caucasus, namely from the Evstafevskaya cleft near Gelendzhik (Birshtein, 1967). This location most likely refers to the sources of the small mountain river Ashamba (Yashamba), which originates on the southern slope of the Markhot ridge and flows into the Black Sea in the area of ​​Golubaya Bukhta (Gelendzhik). Endemism of this region has already been demonstrated in another group of hyporheic crustaceans, representatives of the genus Niphargus Schiödte, 1849 (Crustacea: Amphipoda: Niphargidae) and representatives of the genus Lyurella Derzhavin, 1939 (Crustacea: Amphipoda: Crangonyctidae) (Marin et al., 2021a; Marin, Palatov, 2021b). The new species is morphologically and genetically close to Proasellus linearis. Stable isotope analysis of δ13C and δ15N showed that this species occupies a low trophic position (C1) (-22.67±0.12 for δ13C and 4.40±0.32 for δ15N ), close to the main herbivores in the general scheme of isotope values ​​for macrozoobenthos. A similar trophic position is characteristic of herbivorous crustaceans co-occurring in the springs of the Novorossiysk Gap, such as undescribed species of the genus Niphargus (Amphipoda: Niphargidae), Synurella adegoyi Marin et Palatov, 2022 (Amphipoda: Crangonyctidae) and Gammarus cf. komareki Schäferna, 1923 (Amphipoda: Gammaridae), which probably feed on primary organic matter, such as remains and roots of various forest plants, falling into the hyporheic and groundwater. Currently, 9 species of the genus Proasellus are known from different areas of the Caucasus: P. linearis Birštein, 1967 and P. abini Marin et Sinelnikov, 2024 are known from the western part of the Caucasus region (the Gelendzhik region and the Abin River, respectively), P. mikhaili Palatov & Chertoprud - in the vicinity of the city of Tuapse, P. ljovuschkini (Birštein, 1967), P. similis (Birštein, 1967) and the epigeic species P. cf. infirmus (Birštein, 1936) are known from the southeastern part of the Caucasus region (Khostinsky urban district and Sochi), P. infirmus (Birshtein, 1936) was found in Abkhazia, in springs in the lower reaches of the Gumista River, P. uallagirus Palatov & Sokolova, 2021 was described from North Ossetia, and P. precaspicus Palatov, Dzhamirzoev & Sokolova, 2023 - from the eastern part of the North Caucasus (Dagestan). Molecular genetic analysis has shown that all South Caucasian species of the genus Proasellus represent a monophyletic clade, with the species inhabiting hypogeic/underground habitats in the basins of various local mountain rivers, such as Ashamba, Abin, Pshada, Mezyb, Vulan, and have genetically diverged over the past 2 million years, probably as a result of mountain growth and the separation of karst massifs. Most of the diversity of these crustaceans in the Palearctic remains undescribed, which is also true for the Caucasus, especially the southwestern part of the Caucasus Mountains. The article is published in the international peer-reviewed journal Invertebrate Zoology: Marin I.N., Sinelnikov S.Yu. 2024. A new species of the genus Proasellus (Crustacea: Isopoda: Asellidae) from the Abin River basin, with the preliminary data on the diversity of the genus in the southwestern foothills of the Russian Caucasus // Invertebrate Zoology. Vol.21. No.1: 81–93. Fig.2. Map of collection sites, diversity and phylogenetic relationships of representatives of the genus Proasellus Dudich, 1925 in the southwestern Caucasus Mountains.

Fig.1. The process of collecting mollusks from octocorals. In the photo by researcher E.S. Mekhova (photo by Yu.V. Deart). On coral reefs, where a huge number of animal species live and competition for resources is high, many organisms develop complex adaptations to protect themselves from predators. One way is to become invisible. Sea snails of the Ovulidae family have remarkable camouflage. They reproduce the color and texture of their hosts - various and often different octacorals. Recent research by researchers from the Laboratory of Morphology and Ecology of Marine Invertebrates and the Laboratory of Studying Ecological Functions of Soils at the A.N. Severtsov Institute of Ecology and Evolution of the Russian Academy of Sciences (IEE RAS) on the coast of Vietnam has allowed us to better understand how representatives of one of the species of this family, Phenacovolva rosea, camouflage themselves. The peculiarity of this snail is that, unlike most other species of its family, which can only live on corals of one species, it uses different corals as a host, differing in texture and color, while remaining invisible. "We have managed to identify the mechanism of adaptation of coloration to the color of the host coral. It is associated with the fact that the mollusk, when feeding, integrates coral pigments, such as carotenoids and psittacofulvins, into its body. This discovery opens up opportunities for further study of the genetic and physiological mechanisms underlying phenotypic plasticity," shares her discovery researcher of the laboratory of morphology and ecology of marine invertebrates Sofia Zvonareva. Fig.2. Phenacovolva rosea on different types of host corals. f – mollusk on the coral Menella sp. (photo by E.S. Mekhova). However, a complete match of shades does not always occur. On one of the coral species — Menella sp. — the color of the snails differed significantly more from the color of the host compared to other species, which reduced the effectiveness of the mollusks' camouflage (Figure 2). The reasons why this process is more effective on some corals than on others are not so obvious. It is possible that these discrepancies may be associated with environmental features and the inability of snails to adapt to the chemical protection of some coral species. It is also possible that snails move between corals due to the death of the previous host, but when moving, the mollusk does not have time to adapt or is forced to move to the nearest coral, which may not be optimal for the mollusk's habitat. The work was carried out with the financial support of the Russian Science Foundation (project No. 22-74-00113). The article based on the results was published: Zvonareva, S. S., Mekhova, S. E., & Zaitsev, S. A. (2024). Phenotypic plasticity of Phenacovolva rosea results in various camouflage efficiencies on different coral host species. Marine Biology, 171(4), 71.

Photo: Larvae of a rare rhinoceros beetle are able to effectively process rice straw. Photo by M. Degtyarev In agriculture, especially rice growing, huge volumes of straw are formed, which in moderate climates does not decompose for years. Currently, agricultural producers prefer to burn it, despite the legislative ban on such practice, the threat of fines and massive greenhouse gas emissions, rather than engage in recycling. A promising direction in this area is the search for species of soil invertebrates that are able to eat straw and integrate the carbon contained in it back into the soil, thereby increasing soil fertility. Specialists from the A.N. Severtsov Institute of Ecology and Evolution of the Russian Academy of Sciences (IEE RAS) have found that rhinoceros beetles, as well as some species of woodlice and earthworms, effectively cope with the task of utilizing such residues without increasing greenhouse gas emissions. To solve this urgent problem, IEE RAS specialists conducted an experiment on decomposition of rice straw by various types of soil invertebrates: earthworms, beetles, woodlice, millipedes and other groups. It was possible to establish that the larvae of the rare rhinoceros beetle, listed in the Red Books of some subjects of the Russian Federation, cope with this task perfectly. Also, a widespread type of woodlice (Armadillidium vulgare) and earthworms (Dendrobaena veneta) can decompose rice straw without increasing gross greenhouse gas emissions. "The ability of some large invertebrates to process rice straw without increasing greenhouse gas emissions that we have discovered is important for the implementation of organic farming principles in Russia and the development of the national bioeconomy. In addition, prerequisites are being created for the conservation of rare insect species in culture," said Andrey Stanislavovich Zaitsev, head of the experiment, leading researcher at the Laboratory for the Study of Ecological Functions of Soils and head of the Technology Transfer Center. The results of the work were published in the international journal Pedobiologia: Taxon-specific ability of saprophagous soil macrofauna to reintegrate carbon from agricultural waste into soil, Andrey S. Zaitsev, Anastasia Yu. Gorbunova, Alexander I. Bastrakov, Maxim I. Degtyarev, Donghui Wu, Daniil I. Korobushkin, Ruslan A. Saifutdinov, Konstantin B. Gongalsky, Pedobiologia Volume 104, May 2024, 150958, with the support of the Russian Science Foundation (grant No. 21–74–00126).

On Lake Glubokoe (essays on the history and life of the first Russian freshwater biological station) / compiled by N.M. Korovchinsky. Moscow: KMK Scientific Publications Partnership, 2024. 387 p. The book presents comprehensive information about the history, work and everyday life of the oldest Hydrobiological Station in Russia and the world, founded on Lake Glubokoe in Moscow Province in 1891, where many famous scientists worked and which continues to conduct its scientific and educational activities. The life of the station is described against the background of the socio-political history of the country and the local area. The Appendices to the main part of the publication provide brief biographies of the scientists who worked at the biological station and the people who contributed to its formation and development, as well as a number of materials related to this topic and which have remained unpublished until now or were published in rare, little-known publications. Those wishing to receive a paper version can contact Nikolai Mikhailovich Korovchinsky by e-mail: nmkor@yandex.ru

Figure 1. This is how Franz Leydig saw and described the crustacean Bythotrephes in 1860 (publicly available materials, from: Leydig F. Naturgeschichte der Daphniden. Tübingen, 1860). Currently, human activity plays a key role in the movement of species to new habitats. Despite the huge number of dispersed species, only a small part of them become invasive, that is, harming local communities, associated with enormous ecological and economic damage. According to the most conservative estimates (Cuthbert et al., 2021), the damage from alien species in aquatic systems alone exceeds $ 300 billion, with exponential growth over the past decade. And while some alien species are widely known (for example, the agricultural pest - the Colorado potato beetle or the fouling organism - the zebra mussel), we often do not notice others, although the damage from them can be no less severe. The microscopic branched crustacean Bythotrephes longimanus, or spiny water flea, is a tiny aquatic predator native to the Ponto-Caspian basin. This small predator, hovering in the water thanks to a well-developed compound eye, tracks down prey and actively catches it due to its well-developed locomotor apparatus. Bythotrephes attack almost all planktonic animals, even those significantly larger than themselves, not disdaining their own young, but do not touch sedentary and temporarily attached crustaceans (such as Sida and Simocephalus). Due to such active swimming, this crustacean has a very important morphological adaptation: a thin and very long tail appendage follows the compact body, which serves both to increase the hovering area and to create a straight line of movement, ensuring the stability of the course of this crustacean. It is these features - the long tail spine and the "bloodthirstiness" of the crustacean - that have caused great scientific interest. In aquatic ecosystems of the historical part of the range, for example, in the north of Europe, this species, although capable of reaching high numbers, does not greatly affect local communities. And a completely different situation developed when this species got to the New World. At the beginning of the century, Bythotrephes crustaceans massively settled in the North American Great Lakes. American fishermen were the first to notice these crustaceans: Bythotrephes tail spines cling to fishing lines and clog fishing gear, which has a catastrophic effect on fish catches. Bythotrephes also feeds on small zooplankton, such as small cladocerans, copepods and rotifers, directly competing for food with planktivorous fish larvae. The fish themselves, and especially the fry, also suffer direct harm: when eating bitotrephs, due to their long tail needle, the delicate mucous membrane of the fish's digestive system is injured, mechanically damaged and perforated, which leads not only to illness, but also to mass death of fish, in particular lake herring (Alosa pseudoharengus) in the Great Lakes (Liebig et al., 2021). The total damage to the Great Lakes fisheries is estimated at more than $ 100 million per year (USEPA, 2022). But this is not the only direct damage inflicted on American ecosystems. In a short time, the spiny water flea ate more than half of the biomass of all small filter-feeding crustaceans (primarily Daphnia pulicaria, a key filter feeder that ensures clean water in eutrophic reservoirs of North America). Figure 2. Bythotrephes, photograph from a scanning electron microscope. Visible are the powerful paired swimming antennae (pointing to the right), as well as the powerful grasping limbs (tucked under the body) and the long tail spine (pointing to the left, does not fit in the frame). Photograph provided by the authors of the study. As a result, small algae and cyanobacteria now thrive in the lakes, and their transparency has sharply decreased. According to American experts, the damage from increased water turbidity for Lake Mendota alone exceeded $140 million (Walsh et al., 2016), and the cost of restoring only the ecosystem service of “clear water” for this lake will amount to more than $800 over 20 years for each resident of the coastal zone - an impressive amount, even for US citizens. The work of a large group of authors is devoted to the study of this small but extremely important planktonic predator. The work was published in one of the oldest and highest-rated zoological journals - Zoological Journal of the Linnean Society. Russian scientists played a key role in this study. Thus, the collection and processing of material from the Russian side was carried out by D.P. Karabanov from the I.D. Papanin Institute of Biology of Inland Waters (IBW RAS), and the general supervision of the work was carried out by Corresponding Member of the Russian Academy of Sciences A.A. Kotov from the A.N. Severtsov Institute of Ecology and Evolution of the Russian Academy of Sciences (IEE RAS). Despite such a relevant topic, knowledge about Bythotrephes crustaceans is extremely limited. Thus, even the taxonomic status of Bythotrephes has been discussed for more than 150 years, which indicates the complexity of the classification of this genus. To resolve this issue, the scientists used an integrative approach to taxonomy, which included multigene analysis: four crustacean genes from 80 populations representing at least four morphotypes from different regions (North America, Europe and Asia) were studied to clarify the taxonomic status of Bythotrephes. The results obtained convincingly support the hypothesis that Bythotrephes is a single species, namely Bythotrephes longimanus Leydig, 1860. The scientists suggest that the various morphotypes should be considered ecological forms and accepted as junior synonyms of this species. The study also points to a recent morphological radiation in this species, which may have occurred rapidly and in parallel in the late Pleistocene or shortly after the last glaciation. This suggests that the evolutionary history of these crustaceans is closely linked to climate change. The conducted biogeographic reconstruction of the distribution of Bythotrephes in the Holarctic showed that Europe probably served as a distribution center, from which the crustaceans spread relatively recently, possibly within the last 10,000 years. Several paleographic events are proposed that are important for understanding the biogeography and evolutionary dynamics of Bythotrephes. The study has not only practical application in the form of refining the diagnostic features of Bythotrephes, which is important not only for taxonomic purposes but also for applied identification of crustaceans, but also allows us to understand the historical mechanisms of dispersal of this species in the Holarctic, and therefore to develop methods for combating and controlling unwanted alien species. The work was published in the Zoological Journal of the Linnean Society: A rapid and parallel Late Pleistocene/Holocene morphological radiation in a predaceous planktonic water flea: the case of Bythotrephes (Cladocera: Cercopagididae), Maciej Karpowicz, Dmitry Karabanov, Magdalena Świsłocka-Cutter, Łukasz Sługocki, Elizabeth A Whitmore-Stolar, Joseph K Connolly, James M Watkins, Alexey A KotovZoological Journal of the Linnean Society, Volume 202, Issue 3, November 2024. Related materials: New Science: "A Microscopic Predator with a Global Impact: Scientists Investigate Bythotrephes longimanus" Encyclopedia of Technology: "A Microscopic Predator with a Global Impact: Scientists Investigate Bythotrephes longimanus"

Fig. 1. Results of the principal component analysis for the Shannon index values ​​(a measure of community diversity). The position of individual measurements in the space of the two main explanatory axes and 95% ellipses based on the results of experiments in (A) Kaluga-2019, (B) Kaluga-2020, (C) Krasnodar-2021, (D) Krasnodar-2022. E – comparison of the average area of ​​ellipses. The use of plant residues as mulch is widely used as a method to improve soil quality and maintain crop productivity. The effects of this agricultural practice can be assessed by the state of the soil biota, which largely determines soil fertility. The effect of adding straw-based mulch on the structure of the collembolan community was studied for the first time. The staff of the Laboratory of Soil Zoology and General Entomology of the A.N. Severtsov Institute of Ecology and Evolution of the Russian Academy of Sciences (IEE RAS), PhD in Biology Korotkevich A.Yu., PhD in Biology Goncharov A.A., and Professor of the Department of Zoology and Ecology of the Institute of Biology and Chemistry of Moscow State Pedagogical University, Doctor of Biological Sciences Kuznetsova N.A. conducted four field experiments from 2019 to 2022 on winter wheat fields in two regions of Russia located in different climatic zones - temperate and temperate continental. In each experiment, the effect of adding organic mulch with a known carbon and nitrogen ratio on the structure of the collembolan community was studied. In two climatic zones, the application of mulch stabilized the diversity of the springtail community in the same way, but the ratio of life forms changed differently. The effect of adding mulch on the springtail community was recorded on days 42–54 of the experiment, which is important for planning similar studies. This effect was more pronounced in dry years. The variability of the species diversity of the springtail community decreased threefold when adding mulch with a high nitrogen content (Fig. 1). This indicates that adding mulch leads to stabilization of the diversity of the springtail community during the season. Stabilization of the springtail community indirectly indicates a positive effect of the studied mulching type on the functions of the soil of the agrocenosis. The work was published in the journal Applied Soil Ecology: Anastasia Yu. Korotkevich, Natalia A. Kuznetsova, Anton A. Goncharov, Effect of detrital subsidy on the Collembola community structure in winter wheat agroecosystems, Applied Soil Ecology Volume 203, November 2024, 105676.

Figure 1: Harting's voles are members of a large family group in the laboratory of the Scientific and Experimental Base "Chernogolovka". All members of the group can emit alarm cries at a predator completely synchronously. So far, this is the only mammal species for which such a phenomenon has been discovered. Scientists from Lomonosov Moscow University, Severtsov Institute of Ecology and Evolution of the Russian Academy of Sciences (IEE RAS) and Zoological Institute of the Russian Academy of Sciences studied the acoustic structure of alarm calls in a highly social rodent species, the Harting's vole (Microtus hartingi). The phenomenon of collective explosive emission of alarm calls by several animals that strictly synchronized their calls was discovered and described in detail. Surprisingly, the synchronization of alarm calls was observed not only within groups, but even between neighboring groups of voles. The alarm calls of the Harting's vole remained a mystery for a long time. There was only one article in the literature that described 1 (one!) alarm call, accidentally recorded on a bat detector by a Bulgarian scientist (Pandourski, 2011). This call was surprisingly high-frequency, above 17 kHz, more than twice as high as the alarm calls of other vole species. Although laboratory colonies of Harting's voles have lived happily in captivity for about 20 years, no one has ever heard or recorded alarm calls from them. Therefore, there was a reasonable doubt that the call described did not belong to Harting's vole, but to someone else. In the course of studying the vocal range of the Harting's vole, scientists tried their best to get alarm cries from the animals or to make sure that they are not produced. However, it is not so easy to scare laboratory rodents that grew up in cages and are accustomed to the regular presence of people. Temporary deprivation of shelters, unexpected hand waves, imitation of an aerial predator flying over the cage - nothing helped. Then it was decided to plant groups of voles, consisting of a pair of founders and their cubs aged 2-3 months, in outdoor mesh enclosures. Which would not allow the voles to run away and at the same time protect them from predators. And provide natural predators with access to these enclosures. And provide the voles with a thick layer of sawdust and hay in which they could dig holes. Figure 2: The SongMeter SM-2+ automatic recorder recorded the alarm calls of the voles using two microphones facing away from each other, allowing recordings from two groups of animals to be made simultaneously. To the right and left are two large mesh enclosures, impenetrable to both the voles and their predators. Since humans did not frighten the voles, but scared off potential predators, the cries had to be recorded "blindly". An automatic recorder was used, equipped with two microphones directed at an angle of 180 degrees to each other and simultaneously recording two adjacent groups of voles. Since the recording was done in stereo mode, it was possible to distinguish which group of animals was screaming at a given time by the relative intensity of the signals on the right and left tracks. The stimuli that caused alarm cries in the voles were natural predators that sat on the roofs of the enclosures: magpies, crows, owls, ferrets, feral cats, weasels. Although the predators could not harm the voles in any way, their immediate proximity frightened the voles, causing them to flee into a hole and produce alarm cries. Sometimes the cries of predators along with blows on the net were also recorded. In total, several thousand alarm calls were recorded from ten different family groups, each containing between 4 and 15 voles. Figure 3. The spectrograms show two single alarm calls from Harting's voles and a collective burst that appears as a "chord" of closely spaced or overlapping spectrograms due to the simultaneous or near-simultaneous emission of alarm calls by at least eight of the nine members of the vole group being recorded. An audio file of the sounds is available as Supplementary material to the article on the journal website. Firstly, it turned out that Harting's voles do produce alarm calls, in the form of long series with intervals of several seconds between calls. And these calls are high frequency, on average up to 17 kHz, and the highest up to 22 kHz. Moreover, the main part of the call is located just in the high-frequency region, above 12 kHz, and adults practically do not hear this frequency. Therefore, from the entire sound, people hear only a very short ascending whistle, similar to a bird's. Therefore, it is not surprising that there was no evidence of alarm calls of this species in nature, people simply did not hear them. Figure 4. Spectrograms illustrate natural bursts of collective alarm calls in Harting's voles. Simultaneous calling by several animals can be inferred from overlapping spectrograms of calls emitted nearly simultaneously by several different individuals. (A) Mono spectrogram illustrating overlapping alarm calls of Harting's voles within one family group (B2, consisting of 9 voles); (B) Stereo spectrogram and oscillograms illustrating overlapping alarm calls of Harting's voles within and between two adjacent family groups (B8, consisting of 12 individuals, at the top; B10, consisting of 10 individuals, at the bottom). The oscillograms allow alarm calls to be assigned to each of these groups based on their relative intensities. For example, at 11.6 seconds, the first call is from B8, while the second and third calls are from B10. Audio files with sounds are available as Supplementary materials to the article on the journal website. Secondly, it turned out that Harting's voles often emit alarm cries simultaneously as a group. Moreover, they somehow manage to start screaming before the scream of another animal ends. As a result, the screams are emitted in "bursts" in each of which the screams of several animals are mixed and which are separated by long intervals. Moreover, not only voles of one group can synchronize their screams, but also two neighboring ones, which could hear but could not see each other. This indirectly confirmed that the voles began to scream immediately after receiving an auditory stimulus. So far, this is the only species of mammals for which the phenomenon of complete synchronization between animals when emitting alarm cries at a predator has been discovered. The adaptive biological significance of emitting collective synchronized alarm cries is still unknown. Perhaps this makes the screams more noticeable to members of the family group, perhaps simultaneous screaming allows disorienting the predator, perhaps the number of simultaneously screaming individuals can indicate the degree of threat. But all these assumptions require further study and can be tested not in captivity, but in natural populations of Harting's vole. The results of the study were published in the journal Behaviour: Volodin I.A., Rutovskaya M.V., Golenishchev F.N., Volodina E.V., 2024. Startle together, shout in chorus: collective bursts of alarm calls in a social rodent, the Harting’s vole (Microtus hartingi). Behaviour, v. 161, N 8-9, p. 587-611.