Annotated checklist of the dragonflies ( Insecta : Odonata ) of the Kaliningrad region , north-western Russia .

The first comprehensive surveys on Odonata were made more than 100 years ago, at the beginning of 20 century by La Baume (1908) and especially by Le Roi (1911) and included 50 species. In the following years, no significant publications which particularly address faunistic and taxonomic studies related to the Kaliningrad region were published. Here we present the first modern, most complete checklist of the dragonflies of the Kaliningrad region with notes on the species composition, abundance, and periods of local flight and seasonal migrations. The current checklist is based on data collected by the authors on the Courish Spit (Kaliningrad region, Russia) in 2007-2016. In total, 278 955 specimens belonging to 57 species were recorded. Additional 7 species are included in the list based on the literature data. Thus, the number of species known for the territory of the Kaliningrad region has risen to 64.


Introduction
The dragonfly fauna (Insecta, Odonata) of the Kaliningrad region has received little attention from professional odonatologists.One of the major surveys providing by far the most detailed study on Odonata of this region was published by Le Roi in 1911 and is long out of date.In his publication Le Roi mentioned 50 recorded species for the dragonfly fauna of East Prussia (present day the Kaliningrad region) based on material collected in the 19 th century.Since then no comprehensive studies were conducted over the years with the exception of data on 14 dragonflies species collected during nine days of observations in ornithological traps on the Courish Spit, with Sympecma fusca and Anax parthenope new for the Kaliningrad region (Bertram & Haacks, 1999).The territory of the Kaliningrad region underwent considerable biotopical changes and human habitat disturbance over the past century.These factors, together with climate changes might be expected to affect the species composition of the dragonfly fauna and distribution ranges of dragonflies, as it was shown for some European countries (Ott, 2001(Ott, , 2010;;Hassall et al., 2007;Flenner & Sahlén, 2008;Bernard et al., 2009;Termaat, 2010;De Knijf et al., 2011).Thus, the Kaliningrad region remained one of the most poorly studied areas of Europe.Taking this into account, modern studies are required to provide the most complete to date checklist of the dragonflies and to reveal the characteristics of the dragonfly fauna of the Kaliningrad region, such as number of species, species abundance and periods of local and seasonal migrations.Unlike the Kaliningrad region, dragonflies of adjacent territories and neighboring countries (Poland, Lithuania and Latvia) have been intensively studied over the recent years.According to the literature and newly collected records (see Table 1): 73 dragonfly species have been recorded in Poland (Bernard et al., 2009); 66 dragonfly species have been recorded in Lithuania (Stanionytė, 1993;Bernard, 2002Bernard, , 2005;;Bernard & Ivinskis, 2004;Bernard et al., 2008;Ivinskis & Rimšaitė, 2010;Gliwa, 2013;Gliwa & Stukonis, 2011;Gliwa et al., 2016;Račkauskaitė & Gliwa, 2015); and 60 dragonfly species have been recorded in Latvia (Kalniņš, 2012).The dragonfly fauna of the Kaliningrad region is unquestionably understudied with a total of just 52 species listed.Therefore there was a considerable disparity between the number of species that have been recorded in the Kaliningrad region and neighboring countries.Investigations of the dragonfly fauna and migrations of Odonata that we started several years ago resulted in new and interesting records for the Kaliningrad region itself and Baltic countries as a whole (Shapoval & Buczyński, 2012;Buczyński et al., 2014).The present study summarizes personal observations data of Odonata gathered in 2007-2016 on the Courish Spit in the Baltic Sea and literature data, and provides new insights into dragonfly fauna of the Kaliningrad region.Material and methods On the Courish Spit, Rybachy-type ornithological funnel traps are used for birds migration monitoring.They constitute gradually narrowing cones about 60-70 m long, with a broad entrance (35 m in width and 15 m height) and a small chamber at the end (Fig. 2a).More detailed descriptions of these traps were given by Payevsky (2000) and Shapoval & Buczyński (2012).The traps are located at the boundary between pine forest and sand dunes and allow passive capture of flying birds and also insects: primarily lepidopterans and dragonflies (Shapoval et al., 2005;Shapoval & Shapoval, 2006, 2007;Shapoval & Buczyński, 2012;Buczyński et al., 2014) (Fig. 2b).2012,2013,2016).

Discussion
The number of dragonflies species that occur in the Kaliningrad region has certainly been underestimated previously.Until recently, the comprehensive survey published by Le Roi in 1911 remained one of the main sources for dragonflies data of the Kaliningrad region with 50 mentioned Odonata species.At the end of 20 th century, Bertram & Haacks (1999) published the results of their 9-day observations at the Biological Station Rybachy on the Courish Spit.They recorded 14 species of Odonata, including two new species for the region (Sympecma fusca and Anax parthenope).Since then, no reliable data on Odonata were published.Our data, gathered in 2007-2016, revealed presence of 12 new species for the territory of the Kaliningrad region.
Regarding the fauna of the Courish Spit, 59 dragonflies species have been reported so far for this territory: 57 species were recorded by us, and additional two species (Coenagrion hastulatum, Enallagma cyathigerum) were found in the Lithuanian part of Courish Spit (Stanionytė, 1988).Courish Spit is well known for its bird migration.Annually during migration, millions of birds that avoid sea crossings, use the Courish Spit as a bridge for their flight.Our data shows, that also insects (primarily lepidopterans and dragonflies) use the Courish Spit as a permanent migratory route.Thus, the ornithological traps (particularly Rybachy-type funnel traps), undoubtedly represent a very effective and useful tool for studies on dragonflies (mainly, members of Anisoptera suborder) allowing to detect both mass dragonfly migrations and species involved in individual migrations or movements.Furthermore, ornithological traps help to record rare migrant or wanderer species, which can hardly be observed in the field.The effectiveness of ornithological nets has been previously documented by some other authors (Baccetti et al., 1990;von Rintelen, 1997;Bertram & Haacks, 1999;Borisov, 2009;Thoma & Althaus, 2015).
On the other hand, some species (mainly, members of Zygoptera suborder) do not undertakes significant movements and prefers to stay near water bodies, thus only accidentally can be trapped in ornithological traps.Together with the fact that wetlands, meadows and small lakes are very scarce in the Courish Spit, this suggests that abundance of some species is most likely underestimated and our current data cannot be directly extrapolated to the whole territory of the Kaliningrad region.Thus, further investigation concerning abundance of these species is required.During the study period, a total of 9 specimens were recorded, 8 of them collected in Rybachy-type ornithological traps.Flight period: June -August.According to Le Roi (1911), a common species in East Prussia.Recorded in Poland, Latvia and Lithuania (also found in the Lithuanian part of the Courish Spit).
Calopteryx virgo (Linnaeus, 1758) A total of 19 specimens recorded (maximum 5 specimens per year, in 2008 and 2016).Flight period: late May -August.According to Le Roi (1911), a common species in East Prussia.Recorded in Poland, Latvia and Lithuania (also found in the Lithuanian part of the Courish Spit).

Family Lestidae
Lestes barbarus (Fabricius, 1798) Recorded only in 2010 (a total of 12 specimens collected).Flight period: mid-July -August.According to Le Roi (1911), a rare species in East Prussia.Recorded in Poland; recently added as a new species to the Odonata fauna of Lithuania; not found in Latvia.
Chalcolestes viridis (Vander Linden, 1825) A new species for the Kaliningrad region.A total of 6 specimens recorded, 3 of them were collected on 5.IX.2014.Flight period: mid-July -early September.Not found in East Prussia (Le Roi, 1911).Recorded in Poland, and Lithuania.Not found in Latvia.
Sympecma paedisca (Brauer, 1877) A new species for the Kaliningrad region.A total of 2 specimens collected (09.IX.2009 and25.VIII.2011).Not found in East Prussia (Le Roi, 1911).Recorded in Poland, Latvia and Lithuania (also found in the Lithuanian part of the Courish Spit).Roi, 1911).Recorded in Poland, Latvia and Lithuania (also found in the Lithuanian part of the Courish Spit).

Family Aeshnidae
Aeshna affinis (Vander Linden, 1820) A new species for the Kaliningrad region.Northward expansion of this species became significant in recent years.A total of 25 specimens recorded.Not found in East Prussia (Le Roi, 1911).Recorded in Poland; recently recorded in Lithuania for the first time (Bernard, 2005).Not found in Latvia.
Aeshna grandis (Linnaeus, 1758) A total of 858 specimens recorded.Annually collected in Rybachy-type ornithological traps in moderate numbers (40-200 specimens per year).Flight period: June -mid-September.According to Le Roi (1911), a common species in East Prussia.Recorded in Poland, Latvia and Lithuania (also found in the Lithuanian part of the Courish Spit).
Aeshna isoceles (Müller, 1767) A total of 324 specimens recorded.Flight period: late May -mid-July.According to Le Roi (1911), a rare, occasional species in East Prussia.Recorded in Poland, Latvia and Lithuania.
Fig. 1.Map of the Kaliningrad region.The circle indicates location of the study site on the Courish Spit.

Table . 1
. Checklist of the Odonata species recorded in Poland, Lithuania, Latvia and the Kaliningrad region.
5% of the total number of recorded dragonflies) to 105 786 in 2013 (37,9%).High number of recorded dragonflies in the year 2013 were mainly caused by massive and intensive migration of the following dragonflies species: Libellula quadrimaculata, Sympetrum sanguineum, Sympetrum vulgatum (75 776, 14 532 and 10 373 specimens collected in Rybachytype ornithological traps, respectively).These three species with a grand total of 100 681 specimens collected, constitute 95% of the overall number of dragonflies recorded in 2013.

Table 2 .
List of species and numbers of dragonflies recorded in 2007-2016.
Not collected on the Courish Spit by us.According to LeRoi (1911), a common species in East Prussia.Recorded in Poland, Latvia and Lithuania (also found in the Lithuanian part of the Courish Spit).Not collected on the Courish Spit by us.According to LeRoi (1911), an occasionally common species in East Prussia.Recorded in Poland, Latvia and Lithuania.Not collected on the Courish Spit by us.According to LeRoi (1911), an occasionally common species in East Prussia.Recorded in Poland, Latvia and Lithuania.Not collected on the Courish Spit by us.According to LeRoi (1911), a common species in East Prussia.Recorded in Poland, Latvia and Lithuania (also found in the Lithuanian part of the Courish Spit).According to LeRoi (1911), a common species in East Prussia.Recorded in Poland, Latvia and Lithuania (also found in the Lithuanian part of the Courish Spit).
A total of 2 specimens collected in the meadow in the vicinity of Rybachy village in 2016.Recorded in East Prussia in 1901 (Le , a common species in East Prussia.Recorded in Poland, Latvia and Lithuania.Not collected on the Courish Spit by us.According to LeRoi (1911), a rare species in East Prussia.Recorded in Poland, Latvia and Lithuania.Not collected on the Courish Spit by us.According to LeRoi (1911), a rare species in East Prussia.Recorded in Poland, Latvia and Lithuania.Single specimen (male) collected on 11.VII.2011 in a herbaceous glade in pine forest.According to LeRoi (1911), a common species in East Prussia.Recorded in Poland, Latvia and Lithuania.