Some winter active flies from snow and caves of Vârghiș, Romania

: This paper attempts to fill the gaps in knowledge about the biodiversity of some winter-active fly families from snowfields and caves in Vârghiș, Romania. A total of 15 fly species were recorded from caves and 9 species from snowfields. Exechiopsis ( Exechiopsis ) pseudindecisa Lastovka & Matile, 1974 and Rymosia placida Winnertz, 1863 from caves and Mycetophila mitis (Johannsen, 1912) (all Mycetophilidae) from snow represent the first records for Romania. Habitus photographs of these three species are provided.

Recently, there has been intense climate change (e.g.Musolin, 2007).Observations to date suggest that snow is becoming rarer in many regions of central and southern Europe (Arnell, 1999;Räisänen et al., 2004).Such climatic changes can have a fatal impact on a variety of organisms, including oligostenotermous winter-active insects.
Therefore, it is very important to carry out entomological research also in winter and to concentrate as much information as possible on the occurrence and distribution of winter-active insects.For this reason, in our paper we discuss the winter-with a total length of 1.5 km, collecting was performed only at the opening of the cave and in the first large chambers that have a higher temperature comparing to outside winter temperatures (other parts are not accessible due to barriers installed to protect hibernating bats), 02.02.Insects from the snow were collected by P. Manko, J. Oboňa, A. Dénes, and M. Pál by hand and insects from caves were collected by the same collectors by aspirator and by hand.All samples were placed in tubes with ethanol, then sorted under a stereomicroscope for identification by experts.Diptera identification was performed by specialists as follows: Culicidae L. Dvořák and J. Oboňa; Heleomyzidae K. Dvořáková; Bolitophilidae and Mycetophilidae O. Kurina; Sphaeroceridae J. Roháček; Trichoceridae J. Oboňa.
The material is deposited in the collections of the authors who identified it, or in the collections of the institutions to which they are affiliated.
This species has a relatively wide European distribution from southern Scandinavia to Greece and from Luxembourg to Ukraine (Robert et al., 2019;Huldén & Huldén, 2014;Zittra et al., 2021).Although usually noted as a rare mountain species, it has been found as a relatively common or very common species in underground refuges in the Czech Republic and Slovakia (Dvořák, 2012(Dvořák, , 2014;;Dvořák et al., 2020).On the other hand, this species seems to be really rare in some surrounding countries as documented in recent publications from, e.g., Hungary (Tóth & Kenyeres, 2012), Romania (Török et al., 2018), and Germany (Kampen et al., 2013).
A Palaearctic species, widely distributed in Europe (Chandler, 2013).Larvae develop in terrestrial agarics (Jakovlev, 1994).Adults have been recorded in caves throughout Europe (Weber et al., 2007).It is one of the most commonly recorded Bolitophila species in the cave environment.
Not frequent, but a common European coprophagous species.Adults occur mainly in colder parts of year, and have been caught in traps set during winter (Preisler & Dvořáková, 2009).According to Soszyńska-Maj & Woźnica (2016) it is a very common species on snow in the Beskid Mountains in Poland.
A common European species, often found in caves.Larvae develop in the nests of birds and in the guano of bats (Woznica, 2004).In the colder part of the year it is found outdoors (Preisler & Dvořáková, 2009).Collart (1940) recorded it in Transylvanian caves.
A common Holarctic species, widely distributed in Europe (Chandler, 2013(Chandler, , 2022)).Larvae develop in fruiting bodies of several genera of macrofungi (Chandler, 2022) and adults are found in all types of forest ecosystems.The species has also been recorded from caves in Germany and Luxembourg (Weber et al., 2007;Plassmann & Weber, 2013).This species' name has a problematic identity (cf.Kjaerandsen et al., 2007) and we follow here the interpretations by Zaitzev (2003) and Chandler (2022).
Species of the genus Allodia can reliably be determined only based on the male terminalia.Thus, in most cases, females are determined at the genus level only.
A very common Holarctic species, widely distributed and abundant in Europe (Chandler, 2013(Chandler, , 2022)).Larvae are mycophagous in many genera of macrofungi (Chandler, 2022).It is one of the most frequent fungus gnat species recorded during the winter months in Europe.Adults have been often recorded on snow (Olavi Kurina, pers.obs.) and in caves in Europe (Weber et al., 2007).
Species of the genus Exechia can reliably be determined only based on the male terminalia.Thus, in most cases, females are determined at the genus level only.
A Palaearctic species, widely distributed in Europe (Chandler, 2022).Biology is unknown.The species is very similar to E. (E.) indecisa (Walker, 1856), another widespread Palaearctic species, and the two species may have been confused in some earlier studies.Recorded in caves in Germany, Luxembourg, Slovakia, Norway and Estonia (Weber et al., 2004;Plassmann & Weber, 2013).New for Romania.
A Holarctic species, widely distributed in Europe (Chandler, 2022).Biology is unknown.Adults are described to prefer woodland and carr (Chandler, 2022) and have also been recorded in caves in Germany and Luxembourg (Weber et al., 2007;Plassmann & Weber, 2013).New for Romania.
Species of the genus Mycetophila can reliably be determined only based on the male terminalia.Thus, in most cases, females are determined at the genus level only.
A Palaearctic species, widely distributed in Europe (Chandler, 2022).According to Chandler (2022), the species prefers broad-leaved woodland and has been reared from several species of terrestrial agarics.Adults have been recorded in caves throughout Europe (Weber et al., 2007).
A widely distributed European species (Chandler, 2013(Chandler, , 2022)).Larvae develop in terrestrial agarics (Chandler, 2022).Adults have been recorded in caves throughout Europe (Weber et al., 2007).It is the most commonly recorded Rymosia species in the cave environment.

Rymosia tolleti
A widespread but rare Central European species, with all known records from the cave environment (Kurina et al., 2023).This record has been published in a separate paper (Kurina et al., 2023) with detailed figures of male terminalia, DNA barcode, and discussion of the species' identity.
Species of the genus Trichonta can reliably be determined only based on the male terminalia.Thus, in the majority of cases, females are determined at the genus level only.
It is a typical psychrophilic species that usually inhabits underground habitats (mammal burrows, caves, mines) where its larvae develop in various decaying organic matter (Roháček, 1991).This Euro-Siberian species leaves underground spaces only in the cold season of the year, and therefore, adults (including gravid females) can often be found on snow (for a review of previous records see Dvořák et al. (2022)).Hågvar & Greve (2003) and Dvořák et al. (2022) recorded C. notabilis as the most frequently occurring species of Sphaeroceridae on snow in winter.
Note: There is only one previous record of (probably) C. notabilis from Romania, by Ursu (1982, as Copromyza (Crumomyia) glacialis) from Ciudanoviţ (SW Romania).Inasmuch as the identification by Ursu (l.c.) remains uncertain the species is definitely confirmed from Romania only now.
Three of the recorded species from the family Mycetophilidae (namely Exechiopsis (E.) pseudindecisa, Mycetophila mitis, Rymosia placida) have been recorded for the first time for Romania (for the list of Romanian species see Kolcsár & Salmela (2017)).