SELECTED DIPTERA FAMILIES CAUGHT WITH BEER TRAPS IN THE REPUBLIC OF MORDOVIA (RUSSIA)

We have studied the fauna of several Diptera families caught with beer traps. In this paper, 36 species from 12 Diptera families are reported: four species of Anisopodidae, one species of Bibionidae, one species of Clusiidae, two species of Dryomyzidae, 11 species of Lauxaniidae, five species of Limoniidae, one species of Megamerinidae, three species of Pallopteridae, one species of Piophilidae, one species of Platystomatidae, four species of Sciomyzidae, and two species of Ulidiidae. From these species, three are new for Russia (Calliopum splendidum, Homoneura biumbrata, Sapromyza schnabli, all Lauxaniidae), two new for European Russia (Sylvicola fuscatoides (Anisopodidae), Myennis sibirica (Ulidiidae)). For the Republic of Mordovia and the Mordovia State Nature Reserve, the families Anisopodidae, Clusiidae, Megamerinidae, Pallopteridae, Piophilidae, Platystomatidae, Ulidiidae, and all Lauxaniidae species published in this list are recorded for the first time. Two species from the family Limoniidae (Achyrolimonia neonebulosa and Discobola parvispinula) and three species from the family Sciomyzidae (Euthycera chaerophylli, Tetanocera ferruginea and T. freyi) are recorded for the first time for the territory of the Mordovia State Nature Reserve. Beer traps can be recommended as one of the successful methods for future surveys of Diptera in the area of interest.


Introduction
The order Diptera is among the most diverse insect orders. Its biological diversity contains at least 150 000 species (Courtney et al., 2009), but annually new taxa are being described (e.g., Nourti et al., 2019). Diptera have successfully colonised all continents, including Antarctica, and virtually all habitats except the open sea and inland glaciers. However, the ranges of many species are being studied continuously. Information about the distribution of species and families extends every year (Chursina & Ruchin, 2018a,b;Martín-Park et al., 2018;Astakhov et al., 2019;Gladun, 2019;Pilipenko et al., 2020;Mutin, 2020;Vikhrev et al., 2020). Diptera larvae of different families are found in various terrestrial and aquatic habitats, and can inhabit the tissues of plants and animals; many of them are saproxylic (Martín-Vega & Baz, 2013;Grichanov & Khruleva, 2018;Krivosheina & Krivosheina, 2019).
The Diptera fauna of the Republic of Mordovia is insufficiently known. Plavilshchikov (1964) summarised the knowledge of insects including Diptera from the territory of the Mordovia State National Reserve, and Feoktistov (2011) published new records for the Republic of Mordovia. Recently, the results of systematic studies of some Diptera families were published, including Bombyliidae (Chursina & Ruchin, 2018a), Syrphidae (Chursina & Ruchin, 2018b), Asilidae (Astakhov et al., 2019), Limoniidae, Pediciidae, and Tipulidae (Pilipenko et al., 2020). The purpose of the current study was to analyse the fauna of selected Diptera groups caught using beer traps.
Comments. The occurrence of this species was published by Andersson (1967) and Krivosheina & Menzel (1998) under the name S. fuscatus (Fabricius, 1775) on the basis of the material from Sweden and Asian Russia (Ussuri region). Michelsen (1999) stated that this name belongs to another species and described S. fuscatoides based on the diagnostic figures by Andersson (1967) and Krivosheina & Menzel (1998). After that, several records were published from Poland (Haenni, 2006), Estonia (Kurina, 2006), Finland (Haarto, 2011), and Norway (Söli & Rindal, 2014). The species seems to be a typical eastern boreal species, confined to coniferous forests (Söli & Rindal, 2014). These are the first records from European Russia and the second record outside the boreal zone. The occurrence in the Republic of Mordovia is the southernmost record of this species (Fig. A,B,C). Hitherto, 67 specimens of S. fuscatoides were published from six regions worldwide. However, in this paper, in total 158 specimens are presented from the Republic of Mordovia (Table 1).  Comments. This is a common species, widely distributed across Europe (Dvořák et al., 2019). Krivosheina & Menzel, 1998 Material. MSNR 4: 1 ♂, 1 ♀. MSNR 5: 1 ♂. MSNR 31: 1 ♂. MSNR 35: 1 ♀.

Sylvicola stackelbergi
Comments. The main part of the species range is restricted to Northern and North-East Europe. Isolated records are known from the Netherlands (Beuk, 2002), Slovakia (Ševčík, 2011), Austria (Dvořák, 2014), Armenia , and Romania (Dvořák et al., 2019). In Russia, the species is known from St. Petersburg, Vudyavr (Khibin Mts., Murmansk), Solovetsky Island, Yascera (near Luga, Leningrad region), and Nakhabino (Moscow region) (Krivosheina & Menzel, 1998). Except the high number of S. fucatoides specimens caught during the present study, it is also interesting to compare the number of this species with other species of the genus Sylvicola, as shown in Table 2. Comments. This is a species with a wide European distribution. It has been already known from the Republic of Mordovia (Feoktistov, 2011).
Comments. This is a species with a wide European distribution, except for the southernmost and easternmost parts. It is also known from RU-RUC (Roháček & Merz, 2013 Comments. This is a common and widely distributed species, known from Canada, USA, Europe, Korea, Japan, Russian Far East (Mathis & Sueyoshi, 2011), RU-RUC (Soós, 1984b). Comments. This is a species known from several regions in Canada, USA, Asian Russia, and Europe, except for the southern parts. It is known also from European Russia (Mathis & Sueyoshi, 2011). In the Republic of Mordovia, it has been reported already by Plavilshchikov (1964).

Calliopum splendidum Papp, 1978
Material. MSNR 43: 1 ♀. Comments. This species is known from Western, Southern, and Central Europe and also from the Near East (Merz, 2013). The present record in the Republic of Mordovia is the first for Russia.
Homoneura biumbrata (Loew, 1847) Material. MSNR 42, AL: 1 ♂. Comments. This is a rare species known from western and middle parts of Europe (Merz, 2013 Comments. This species is known from most of Europe, and also from RU-RUC (Merz, 2013 Comments. This species is known from most of Europe, the Near East, and North America, and also from RU-RUC (Merz, 2013). Comments. This species is known from most of Europe, and also from RU-RUC (Merz, 2013).

Sapromyza schnabli Papp, 1987
Material. MSNR 37: 1 ♀. Comments. This is a poorly known European species, recorded only from some countries: Austria, Belarus, the Czech Republic, France, Hungary, Poland, Romania, Slovakia, and Switzerland. It is the first record for Russia.

Tetanocera freyi
Comments. This is a species of Western and Northern Europe, known from France to North European Russia and also from North America (Rozkošný, 2013). It is the first record for RU-RUC.

Affinity to forest types
For the comparison of the frequency occurrence of the caught species, all localities were divided into established in deciduous forest (22 localities), mixed forest (27 localities), and pine (Pinus sylvestris L.) forest (14 localities). Of 36 species identified during the survey, 27 species were trapped in deciduous forest, 24 species in mixed forest, and only 13 species in pine forest. Noteworthy, the species Dryope decrepita and Calliopum splendidum were trapped only in pine forest.
-Percentage of localities in each forest type, where the species was found. Almost all species were found to be the rarest in the mixed forests. Three common Sylvicola species (S. cinctus, S. fuscatoides, S. punctatus) occupied considerably more localities in deciduous and pine forests than in mixed forests. Bibio clavipes was trapped noticeably most often in pine forest, while Dryomyza anilis and Metalimnobia quadrimaculata in deciduous forest. Interesting is the trapping of Meiosimyza subfasciata in mixed forest, while it was absent in both other forest types. Evaluating of all 13 species shows that nine of them have the highest average abundance in deciduous forests, two of them in pine forests, and two of them in mixed forests.
-In each forest type, the average abundance of species counted as the sum of specimens in the forest type divided by the number of localities in this forest type. Three common Sylvicola species (S. cinctus, S. fuscatoides, S. punctatus) were more abundant in deciduous and pine forests compared to mixed forests. Bibio clavi-pes was most abundant in pine forests, while Dryomyza anilis in deciduous forests. Metalimnobia quadrimaculata was abundant in deciduous forests, less abundant in mixed forests, and non-abundant in pine forests. The evaluation of seven species (as the differences in the other six were minimal) shows that five of them have the highest average abundance in deciduous forests, two of them in pine forests, and none of them in mixed forests.
-Maximum abundance of specimens in one trap. The analysis shows almost the same results as in the previous paragraphs. Sylvicola spp. had the highest abundance values in deciduous and in pine forests, Bibio clavipes in pine forests, Dryomyza anilis in deciduous forests, and Metalimnobia quadrimaculata in deciduous forests and slightly lower in mixed forests. Meiosimyza rorida has a higher abundance in mixed forests and slightly lower abundance in deciduous forests compared to pine forests. The evaluation of 11 species (as the differences in the other two were minimal) shows that seven of them have the highest abundance in deciduous forests, two of them in pine forests, and two in mixed forests.

Discussion
Concurrently with advancing research in the fields of ecology and nature conservation, taxonomists have acquired a considerable amount of knowledge in species diversity. The availability of this scientific knowledge varies greatly over space, time, taxa, and type of information, creating gaps in biodiversity information (Amano et al., 2016). Particularly Diptera are often exemplary in this respect. The knowledge of the biodiversity is crucial from the conservation point of view. Collecting in the Republic of Mordovia was designed to reduce the gap in the knowledge of Diptera and other invertebrates. Very popular, efficient, cheap and simple passive methods of insect sampling are bait traps (e.g., Manko et al., 2019;Dvořák et al. 2019). Beer (with various additions and modifications) is very commonly used as bait, attracting especially Diptera, Mecoptera and other insect groups (e.g., Dvořák et al., 2017;Oboňa et al., 2017). This method is very attractive because it can be also used for monitoring of the occurrence and distribution of pests or parasites; furthermore it is able to capture rare and little-known species (e.g., like in the pres-ent study). A thorough knowledge of biodiversity is a suitable pillar for further special and applied research.
By analysing the results of dominancy, frequency, and affinity to forest types we can assume that Sylvicola fuscatoides, S. punctatus, and S. stackelbergi had the optimum in deciduous forests with the respect to all three above mentioned parameters, and Sylvicola cinctus in pine forests. All four Anisopodidae species had the lowest abundance in mixed forests. Bibio clavipes was the most frequent and abundant in pine forests, less abundant in mixed forests, and least abundant in deciduous forests. Completely other abundance values were found for Dryomyza anilis, which was abundant in deciduous forests, and less abundant in mixed and pine forests. No considerable differences were found for Lauxaniidae species, but members of this family occurred less frequently in pine forests. Data for Metalimnobia bifasciata did not show any remarkable results, while Metalimnobia quadrimaculata had preferences similar to those for Dryomyza anilis, being abundant in deciduous forests and less abundant in mixed and pine forests. Platystoma lugubre occurred almost evenly everywhere. But it seems that it slightly prefers deciduous forests. No species of the families Pallopteridae and Sciomyzidae were found in pine forests. All Ulidiidae species were found only in deciduous forests.
The obtained results show that the deciduous forests are the most diverse in terms of Diptera species. The results obtained in mixed forests were similar to deciduous forest. But this forest type is not so diverse in terms of species. In the pine forests, the species composition was the least diverse, some species are missing or less abundant compared to deciduous and mixed forests. At the localities MSNR 41 and MSNR 42, the traps were hung on different trees at two heights, named as «low» (1.5 m) and «high» (5-7 m) on various tree species: Tilia cordata Mill., Betula pendula Roth, Alnus glutinosa (L.) Gaertn., Quercus robur L., Pinus sylvestris L. Abbreviations added to the locality name refer to tree species (T: Tilia cordata, B: Betula pendula, A: Alnus glutinosa, Q: Quercus robur, P: Pinus sylvestris) and height (H: high, L: low).