Checklist of the Coleoptera of Mordovia State Nature Reserve, Russia

Abstract All 2,145 species of Coleoptera from 88 families known to occur in Mordovia State Nature Reserve, Russia, are listed, along with their author(s) and year of description using the most recent classification framework. Adventive species for European Russia are indicated. There are 31 adventive species in the reserve, comprising 1.44% of the total beetle fauna.


Introduction
Rapid environmental changes due to urbanization and climate change have recently had a major impact on biodiversity (Czech et al. 2000, Kottawa-Arachchi and Wijeratne 2017, Rozhnov et al. 2019, Zamotajlov et al. 2019. In particular, the application of modern technologies in agriculture, ongoing deforestation, and changes in land use due to urbanization, cause the loss of biodiversity (Myers and Knoll 2001, Novacek and Cleland 2001, Lambin et al. 2003, Kestemont 2019. That is why the value of protected area (nature reserves and national parks) is steadily increasing. Moreover, in order to preserve biodiversity, it is necessary to identify key factors determining the distribution of species in their habitats. Such studies can be carried out in territories that were little affected by human activity; these territories are called protected area (Basset et al. 2007, Grebennikov 2016. The term biodiversity hotspot is commonly used for regions or areas with high species richness, genetic richness, evolutionary important areas of origin, etc. (Reid 1998, Médail and Quézel 1999, Zagmajster et al. 2008, Silva and Ferreira 2016, Kumar et al. 2020. At the same time, in the most developed areas, such biodiversity hotspots are protected areas. Protected areas usually occupy certain areas in natural and climatic zones and include typical ecosystems of such climatic zones. In the forest natural zone, such areas are sparsely touched woodlands, these are different types of steppe areas in steppe. Currently global Protected Area Network covers approximately 14.9% of the world's terrestrial land surface (Belle et al. 2018). Inventorying all biota is the best way to study biodiversity in the area (Weibull et al. 2003, Grebennikov 2016, Negrobov et al. 2018. However, such studies may often not be carried out due to limitations in the field of human resources and, therefore, certain insect families or ecological insect groups that are bioindicators are more often used (Lindenmayer et al. 2006, Lachat et al. 2012, Pozsgai and Littlewood 2014, Polevoi et al. 2018, Prokin et al. 2019). On the other hand, the faunal analysis of individual insect orders can be carried out for a certain time; the data generated can then be used to compile a checklist of species and further analyze the spread of species, their distribution in the territory, settlement routes, etc. This can only be done if the most diverse methods covering all ecological groups of insects are applied (Basset et al. 2007); hence this checklist of the Coleoptera (Insecta) of Mordovia State Nature Reserve, based on a variety of methods.
The Mordovia State Nature Reserve was established in 1936. It is located in the Temnikov district of the Republic of Mordovia (European Russia) on the forested right bank of the Moksha River and covers an area of 321.62 km 2 (Fig. 1). From the north, the border runs along the Satis River (the right tributary of the Moksha), further to the east along the Arga River, which flows into the Satis River. The western border runs along the Chernaya, Satis, and Moksha rivers. From the south, the forest-steppe approaches naturally delineating the boundary of the reserve massif. By natural zoning, the forest tract of the Mordovia State Nature Reserve belongs to the zone of coniferous-deciduous forests on the border with the forest-steppe. Forest communities occupy 89.3% of the total territory (Ruchin and Egorov 2017b). In general, the vegetation cover of the Mordovia State Nature Reserve has a taiga character with tendency towards a nemoral (broad-leaved) forest type during successions. The intermix of forest-steppe elements is typical for this territory. Pinus sylvestris L. is the dominant forest tree in the Mordovia State Nature Reserve. It forms pure or mixed communities in the southern, central, and western parts of the reserve. Betula pendula Roth stands are the second largest forest type in the reserve. These are predominantly secondary communities at the sites of cut and burnt pine forests. Especially, many young birch stands developed at places damaged by the wildfire in 2010. Tilia cordata Mill. stands are located mainly in the northern part of the Mordovia State Nature Reserve. These are also secondary plant communities that arose on the site of pine forests and lime-spruce forests. Quercus robur L. forests occupy a relatively small area of the Mordovia State Nature Reserve. They are common in the Moksha River floodplain in the western part of the reserve. Picea abies L. and Alnus glutinosa (L.) Gaertn. stands are located mainly in floodplains of rivers and streams (Pushta, Vyaz-Pushta, Vorsklyai, Arga, etc.) and occupy small areas (Stojko and Senkevich 2018). Plant communities of small-leaved tree species (birch, aspen, alder) are formed in burnt forest areas (Khapugin et al. 2016, Vargot 2016. The main areas of floodplain meadows are located along the Moksha River in the south-west of the Mordovia State Nature Reserve. Previously, studies were carried out for individual orders and families of the arthropod fauna of the Mordovia State Nature Reserve, in particular for the Neuroptera and Raphidioptera Makarkin 2017, Makarkin and, Hymenoptera (Ruchin and Antropov 2019), Orthoptera (Ruchin and Mikhailenko 2018)

Notes
This checklist includes data on 2145 species from 88 families (Table 1); the Ptiliidae and Clambidae collected in the Mordovia Nature Reserve remain to be identified. The occurrences of Spercheidae, Psephenidae, Drilidae, and Stenotrachelidae in the reserve is possible but not yet confirmed.
The most diverse families (Carabidae, Staphylinidae, Cerambycidae, Chrysomelidae and Curculionidae) make up a total of 57.6% of the Coleoptera diversity of the Reserve. Forty-seven species from 20 families are listed for the first time for the Mordovia State Nature Reserve and the Republic of Mordovia. Detailed information about them will be published separately.

Discussion
The Mordovia State Nature Reserve is a unique refugium of forest that has been little affected by human activity for many centuries . This has preserved very rare species that are known from single records in the center of the European part of Russia: Ilybius wasastjernae (Dytiscidae), Aleochara falcata, Alevonota egregia, Atheta sequanica, Bledius fergussoni, Gyrophaena nitidula and Sepedophilus binotatus (Staphylinidae), Agrilus kaluganus (Buprestidae), Isorhipis melasoides (Eucnemidae), Denticollis rubens and Ampedus nigerrimus (Elateridae), Erotides nasutus and Lopheros lineatus (Lycidae), Allonyx quadrimaculatus (Cleridae), Ipidia sexguttata (Nitidulidae), Cucujus cinnaberinus (Cucujidae), Clemmus troglodytes (Anamorphidae), The Mordovia State Nature Reserve is important for the conservation of rare Coleoptera species. It is home to eight species listed in the Red book of the Russian Federation (Ruchin and Kurmaeva 2010, Ruchin and Egorov 2017b: Dytiscus latissimus, Trypocopris vernalis, Ceruchus chrysomelinus, Osmoderma barnabita, Protaetia speciosissima, Protaetia fieberi, Elater ferrugineus and Melandrya barbata. Trypocopris vernalis, Elater ferrugineus and Melandrya barbata are only found only in the territory of the Mordovia State Nature Reserve within the Republic of Mordovia. The Coleoptera fauna contains 31 adventive species as currently known (1.44% of beetle species diversity) from 17 families ( Table 1). The largest number of adventive species has been recorded in the families Staphylinidae (4 species), Dermestidae, Nitidulidae and Tenebrionidae (3 species each). The small proportion of adventive species in the fauna possibly indicates the stability of the ecosystems of the Mordovia State Nature Reserve and the weak anthropogenic impact on them.
The obtained results on the diversity of beetles in the Mordovia State Nature Reserve can be compared with similar data from other protected areas with well-studied Coleoptera both in Russia and in other countries (see Table 2).
Analysis of the data on the degree of study of the beetle fauna in natural protected areas of the European part of Russia allows us to conclude that the beetle fauna of the Mordovian State Nature Reserve is the most studied.
The study of the beetle fauna of the Mordovia State Nature Reserve needs to be continued. The families Helophoridae, Hydraenidae, Leiodidae, Elmidae, Throscidae, Cryptophagidae, Phalacridae, and Scraptiidae have not been sufficiently studied and require particular attention.