Contribution to the knowledge of the spring butterfly fauna of the Republic of Macedonia (Lepidoptera: Papilionoidea & Hesperioidea

. In spring 2010, we encountered 60 butterfly species during field surveys centred mainly in the under-surv eyed southeastern part of the Republic of Macedonia. We visited 23 localities, where several interesting observations were made. Among these, new sites of some rare species such as Pontia chloridice , Pieris krueperi, Plebejus sephirus, Scolitantides orion , Tarucus balkanicus , Melitaea ornata , Carcharodus orientalis, and Erynnis marloyi should be mentioned. Such a high number of species observed indicates an overall high butterfly diversity of this region, particularly in the lower Vardar valley. Here, several specific habitats hosting rare and threatened species were discovered. The anthropogenic pressure on important butterfly habitat is still low in the surveyed area; however, the first signs of large scale abandonment are already visible.


Introduction
Butterflies are commonly one of the best studied groups of insects in countries where systematic faunistic surveys are sparse.The Republic of Macedonia is no exception with first large scale survey dating back to Rebel (1913) and Alberti (1922).A list of species with an overview of published records followed in 1964 (Thurner 1964) and in 1989, when a butterfly atlas was published by Schaider & Jakšić (1989).The grid size of the atlas is 10x10 km, which provides a good overview of butterfly distribution in the country.The negative side of the atlas is the non discriminatory use of all records, including questionable observations, making some maps misleading.Among the species not confirmed by recent surveys, the Lycaena ottomana (Lefèbvre, 1830), Plebejus dardanus (Freyer, 1844), Erebia alberganus (de Prunner, 1798), and Pseudochazara graeca (Staudinger, 1870) are the most prominent examples.
In the years that followed the atlas, several additional species were discovered (Krpač & Mihajlova 1997, Micevski et al. 2009, Thomas 1993, Verovnik & Micevski 2008, Verovnik et al. 2010), bringing the total of species known in Macedonia to 203.The list is still not complete and several additional species whose range is close to Macedonia are still expected to be found.This makes the Republic of Macedonia one of the butterfly richest countries in Europe, especially considering its small size.The main factor influencing the high diversity is the predominantly mountainous relief with several high mountain ranges and steep gorges providing microclimatic conditions for species whose range in Europe is very limited.Such regions, especially the Treska gorge, are also among the best surveyed in Macedonia, leaving relatively large areas of the country still unexplored or understudied.
The main aim of our study was to add faunistic records for spring butterflies in the sparsely surveyed south-eastern part of Macedonia.These records are particularly valuable, as spring occurring species are less studied than those flying in summer in high season for the majority of butterfly species.During our surveys we tried to cover a wide variety of habitats present in this region to provide for a complete overview of the butterfly fauna.

Material and methods
Our field survey was conducted between 24.4.2010 and 1.5.2010.In total, 23 localities were visited (Fig. 1).The selection of sites and regions with potential interesting habitat was made before the trip with the use of Google Earth images.Adult butterflies were netted using entomological nets and released after identification, or identified in nature.

List of species
Butterflies are listed in taxonomical order following the nomenclature of the Red List of European Butterflies (van Swaay et al. 2011).As butterflies were not collected and genitalia were not measured, we list Leptidea sinapis as Leptidea sinapis/juvernica species complex.

Discussion
In many cases, the early spring butterfly fauna is less studied compared to the peak season in June or July, especially in the countries where faunistic data are published mainly by foreign authors.The Republic of Macedonia is no exception, therefore distribution of several species with flight period limited to the spring is not well known.In order to fill this gap, we surveyed large part of the country, but stayed mostly in the warmer lowland regions where diversity of butterflies was expected to be higher in early season.Thus we concentrated on the surveys of the Vardar Valley and wider surroundings of Lake Dojran.A total of 60 species observed is extremely high for the survey in the last week of April and it could be attributed to the early season due to favourable weather conditions in spring 2010.
The commonest species during the survey was Callophrys rubi, which was recorded at 21 sites.It is interesting to note that its recorded distribution in Macedonia is rather patchy (Schaider & Jakšić 1989).It was recorded from many new squares during our survey.As this is an exclusively early spring occurring species, our records indicate its much wider distribution in Macedonia.Among the species normally not flying in April, the following early records are interesting: Plebejus sephirus, Polyommatus bellargus, Melitaea trivia and Pyrgus sidae.We paid special attention to specific habitats during our surveys, where rare and local butterfly species were expected to be found.These are dealt with in detail bellow: • Pontia chloridice -It is a habitat specialist utilizing sites with regular disturbance enabling its host plant Cleome ornithopodioides to grow (John et al. 2008).It was observed at two sites on gravels along streams near Gevgelija.These finds and its occurrence in Macedonia have been recently reviewed by Franeta et al. (2011).
• Pieris krueperi -Another habitat specialist limited to warm rocky gorges.We found it in the Topolka valley, from where it had already been reported by Thurner (1964), and at a new site north of Gevgelija on the rocky slopes above the Vardar River at Gavato village.This is the first record of the species from the lower part of the Vardar Valley in Macedonia.
• Plebejus sephirus -This is a predominantly mountainous species in the southern part of the Balkan Peninsula.The presence of a single male in the gorge east of Besvica village to the south from Demir Kapija was therefore a big surprise.The larvae of this species are feeding on Astragalus sp., possibly on A. excapus in Macedonia (Tolman & Lewington 2008).Non-flowering plants of an unidentified Astragalus were observed on dry sandy meadows at the site.
• Scolitantides orion -According to Schaider & Jakšić (1989), the species is rare in Macedonia and mainly limited to the western part of the country.It is again a habitat specialist utilizing screes and rocky areas, where its host plants Sedum sp. are growing.
We found it on wide gravels SE of Strumica and on eroded slopes along the path at Vodoča dam.These are the first records from SE part of Macedonia.
• Tarucus balkanicus -The species has a very limited range in Macedonia with records scattered mainly in the southern half of the country (Schaider & Jakšić 1989).We found it in the Topolka Valley, where it had already been discovered by Thurner (1964), and at two new sites at nearby Kočilari in the Vardar Valley further south from the Topolka and in the gorge east of Besvica village near Demir Kapija.
• Melitaea ornata -This species was first mentioned for Macedonia by Verovnik et al. 2010 under the name Melitaea telona.Due to its morphological resemblance to a more widespread but not closely related M. phoebe (Leneveu et al. 2009), the status of M. telona was disputed until recently.Currently it has been confirmed that it is conspecific with and is a junior synonym of M. ornata from the European part of Russia south of the Urals (Tóth & Varga 2011, Tóth et al. 2012).Although the species can be identified safely only by adult larvae and their ecology (Russell et al. 2007), typically marked adults can also be provisionally assigned to one or another species.Additionally, the early occurrence in April is a good indication for M. ornata, as M. phoebe usually starts to fly from mid-May onwards (Tolman & Lewington 2008).We found putative M. ornata specimens with typical external characteristics at 8 new sites covering almost the entire surveyed area from the Strumica Valley in the east, to Lake Dojran and the middle part of the Vardar valley.The search for larval stages and host plants will be required to precisely delimit the distribution of M. ornata in Macedonia, and our records provide a good starting point for such surveys.
• Carcharodus orientalis -Due to its resemblance to Carcharodus flocciferus (Zeller, 1847), this is another poorly studied species in Macedonia.We found it at four sites, three in the wider surroundings of Lake Dojran and in Demir Kapija in the Vardar Valley.These records provide a further extension of the species' known range in Macedonia.
• Erynnis marloyi -This species reaches its northwestern limit in Macedonia and is therefore extremely rare and local, limited to the warmest regions, where it is usually confined to rocky gorges.This corresponds well with both sites, where it has been recorded during recent surveys.A single specimen was seen both in the gorge east of Besvica village near Demir Kapija and in the Treska Valley in a small gorge at Kozjek Lake dam.  ).This assessment should, however, be considered tentative, as for many of the listed species the distribution and habitat requirements in Macedonia are not sufficiently known to allow designation of threat categories.Pseudophilotes bavius, for example, has been reliably recorded only from two sites in Macedonia (Thurner 1964) and not confirmed at Veles site in recent decades.The abundance of adults in the Treska-Matka Gorge has been steadily declining during last two decades due to overgrowing (pers.observ.)and it is not unlikely that the species is on the verge of extinction in Macedonia.Its presence at Kozjek Lake dam further upwards in the Treska Valley provides some hope it is still surviving in other localities along the river.

Based on the recent
Once again, Macedonia has proved to be one of the most interesting counties for butterflies in Europe.Our survey provides a good overview of the spring butterfly fauna of the southeastern part of the country.However, only a more systematic approach targeting all under-surveyed regions would be required to fully understand the species distribution and endangerment.We hope this contribution will be seen as a step in this direction.

Figure 2 .
Figure 2. The Inky Skipper (Erynnis marloyi), a rare species in Macedonia, was found at two sites during the survey (photo: Rudi Verovnik).

Table 1 .
The distribution of butterfly species observed during the spring field survey in Macedonia in 2010.The localities are numbered as in the List of localities chapter.D&S stands short for Denis & Schiffermüller.Tabela 1. Razširjenost dnevnih metuljev, opaženih med pomladansko raziskavo v Makedoniji leta 2010.Lokalitete so oštevilčene kot v poglavju seznam lokalitet.D&S je okrajšava za Denis & Schiffermüller.
European Red List of Butterflies (van Swaay et al. 2010), only two of the observed species Zerynthia cerisy and Pseudophilotes vicrama are listed as near threatened at the continental level.Both are widespread in Macedonia (Schaider & Jakšić 1989) and possibly locally not threatened.Zerynthia cerisy actually prefers a certain degree of habitat disturbance and it is commonly observed near or even within villages, where the host plant Aristolochia clematitis is growing (pers.observ.).Following the Red List of Butterflies for the Macedonian Republic (Krpač & Darcemont 2012), several additional threatened species found during our survey are listed: Erynnis marloyi (NT), Zerynthia polyxena (NT), Euchloe penia (VU), Pieris krueperi (NT), Pontia chloridice (VU), Tarucus balkanicus (NT), Pseudophilotes bavius (VU), and Scolitantides orion (NT