Vol 104, No 10 (2025)

The larva and nymphs of Pergalumna emarginata (Banks, 1895) (Oribatida, Galumnidae) are described, based on material collected from bogs and pine-birch forests in Western Siberia, Russia. The juvenile instars are characterized by the following morphological characters: rostrum acute or narrowly rounded, rostral and lamellar setae medium-sized, interlamellar and exobothridial setae short and erect, bothridial seta long, lanceolate and barbed, a gastronotic porose areas present, setae of gastronotic macrosclerite minute, gastronotic seta c₃ longer than c₁ and c₂, gastronotic setae each with a small sclerite at base, a median pore present, lateral part of body with several oblong sclerites, anterior margin of coxisternum overlapping medially, posteroventral region with one pair of large sclerites, some leg segments with thick setae. Differences between the juvenile instars of P. emarginata and other known Pergalumna species are listed. Identification keys to the larvae and tritonymphs of Pergalumna are provided.

The prevalence of Plasmodium, Haemoproteus, and Leucocytozoon haemosporidian infections was investigated at three stations of the Khingan Nature Reserve, Amur Region, Russian Far East. Between 2021 and 2024, we sampled mainly passerine birds, with a total of 751 individuals belonging to 68 species. Birds were mist-netted during the breeding season at the “Kleshenskii” and “Karapcha” stations, and during the spring and autumn migrations at the “Lebedinii” station. The prevalence of different haemosporidian genera varied between “Karapcha” (coniferous–deciduous forest) and “Kleshenskii” (swampy plain with forest patches): Plasmodium and Leucocytozoon parasites were significantly more common at the “Karapcha” station, while Haemoproteus parasites dominated at the “Kleshenskii” station. Based on these data and on infection patterns in resident bird species, we hypothesize that haemosporidians from all three genera can be transmitted at “Karapcha”, but only (or mainly) Haemoproteus at “Kleshenskii”. Long-distance migrants had a higher prevalence of Plasmodium than sedentary bird species at both “Kleshenskii” and “Karapcha”. We assume that Plasmodium parasites are also actively transmitted on the wintering grounds. At the “Lebedinii” station, the frequency of Leucocytozoon infections was higher in autumn than in spring. This pattern could be related to parasite transmission in the northern latitudes where the birds migrating through “Lebedinii” breed. In general, birds can become infected by haemosporidians either (1) on the breeding grounds or (2) on the wintering grounds and during migration. Our study revealed that, among breeding birds, location (i. e. “Kleshenskii” vs. “Karapcha”) most strongly affected the infection prevalence, whereas among migrants at “Lebedinii”, season (spring vs autumn) was the key factor. Whether a species was resident or migratory rendered a much smaller effect. We thus conclude that, in our study area, the prevalence of haemosporidian infection depended more on breeding-ground conditions than on those at the wintering grounds.

The Japanese Big-footed bat, Myotis macrodactylus, is a protected and vulnerable Far Eastern bat species. In Russia, the distribution range consists of two isolated parts: the south of Primorsky Krai and Kunashir Island. Three morphological subspecies have been distinguish in the Japanese Big-footed bat: the nominotypical one, distributed on the Japanese islands, M. m. continentalis, described from the southern Primorye, and M. m. insularis, presumably living on the Kunashir Island. Nevertheless, the intraspecific variability in the mainland part of the range, as well as the genetic differences between the subspecies, remains unknown. The work we carried out allowed us to identify for the first time two highly divergent mitochondrial lineages in M. macrodactylus with an average p-distance between them amounting to 3.97%, indicating a subspecific level of divergence. The Insularis lineage is distributed on the Japanese islands and Kunashir Island, this coinciding with the supposed range of the nominotypical subspecies, as well as in South Korea, including the Jeju Island. The Continentalis lineage is revealed exceptionally in the southern Primorye and in adjacent areas of northeastern China, this correlating with the supposed range of M. m. continentalis. In contrast to the mainland lineage, the island one is more strongly differentiated and contains at least four clades (I–IV) with unclear distributions. All M. macrodactylus studied from the Kunashir Island belong to Clade I, prevailing on Honshu and Hokkaido, within which they are characterized by the lowest nucleotide diversity. The Continentalis lineage is characterized by a star-like structure with the predominance of the central haplotype, while the greatest genetic diversity was identified in the Primorsky Krai, this possibly indicating a favorable position of this rare protected species’ population.

The biology and a history of the decline of the Arctic fox population on the Mednyi Island, Commander Islands, North Pacific, are considered. Currently, this is the smallest and possibly the most ancient island population of canids on Earth. Among the endemics of island faunas, carnivores are generally very rare, among the canids only the California Island fox (Urocyon littoralis) being listed in taxonomic and conservation databases. Questions regarding the species status and phylogenetic history of Commander Arctic foxes, Vulpes lagopus beringensis (Merriam, 1902) and V. l. semenovi (Ognev, 1931), remain open until genomic studies are conducted. Over thousands of years, Commander Arctic fox populations have evolved in an environment radically different from that of the continental Arctic foxes: under conditions of complete isolation, ecological stability, and a mild climate, with neither predators nor competitors from other species. The behavioral ecology of the Island Arctic fox has been adapted to life in a super-dense population, where severe intraspecific competition and the risk of inbreeding are prevalent. This adaptation has led to a complete restructuring of the social, reproductive, territorial, and spatial behavior of the Island Arctic fox. Historically, the viability of the Mednyi population has been supported by its stable and relatively high population size (over 1,000 individuals). Since the discovery of the Commander Islands in 1741, intensive fox trapping on Mednyi Island continued for over two centuries. In the last 40 years, hunting has been accompanied by supplementary feeding. After the cessation of fox trapping and supplementary feeding in 1965, the population size began to be determined solely by the island ecosystem’s natural capacity, which decreased significantly during the second half of the 20th century. The long-term decline in effective population size and artificial selection have led to a significant loss of genetic polymorphism. Genetic degradation and a decrease in the carrying capacity of the island ecosystem have placed the population in a critical situation. A sudden outbreak of ear mange in the late 1970s, which caused the death of 90% cubs, demonstrated the enormous risk associated with the emergence of new pathogens. In the recent years, the abundance of food sources (such as deposits of storm-cast macrophytes, the number and size of seabird colonies, and the number of sea otters) has noticeably diminished, and the Mednyi Arctic fox population has declined to fewer than 60 individuals. The National Park protection regime and the inclusion of the Mednyi Arctic fox in the Red Data Book of the Russian Federation are not sufficient to prevent the population from going extinct. The situation requires targeted conservation measures to protect this disappearing island endemic.