Further records of social parasitic ants in Europe and review of the Bulgarian species.

Background: Social parasitic ants exploit the colonies of other ant species, either permanently or temporarily. The permanent parasites are amongst the rarest species of ants, although their hosts may be very common. Due to their rarity and often restricted distribution range, most of them are listed as vulnerable. Filling in the gaps in geographical and host ranges will advance our understanding of the social parasitic lifestyle's origin and evolution. New information: This study reports the first records of the slave-makers Myrmoxenusalgerianus (Cagniant, 1968) for Europe (Italy, Sicily) and M.ravouxi (André 1896) for Albania and the inquiline Anergatesatratulus (Schenck, 1852) for Malta (Gozo). We also report new localities of Camponotusuniversitatis Forel, 1890 for Albania and Myrmoxenusgordiagini Ruzsky, 1902, M.kraussei (Emery, 1915) and Anergatesatratulus for Bulgaria. Diversity, type of parasite-host relationships, host range, distribution and conservation of social parasitic ant species in Bulgaria are discussed. Although social parasitic ants are still understudied in Bulgaria, they represent 21% of the regional ant fauna.

Review of the Messorsemirufus complex (Hymenoptera, Formicidae) in Greece.

Messor is a diverse genus of Myrmicinae with 168 extant species and subspecies. In the Mediterranean, some of its taxa historically were classified as members of the Messorinstabilis group (sensu Santschi), of which 19 are known from the eastern Mediterranean. Here, the Messorsemirufus complex of the Balkan Peninsula that assembles a distinct subsection of members of the instabilis group is defined and treated. In total, five species are recorded, including three that are new. Messoratanassovii Atanassov, 1982 is redescribed and confirmed for Bulgaria (Thracian Plain, Struma, and Mesta Valley, Pirin Mt., and Eastern Rhodopi) and Greece (Epirus, Ionian Islands, Central and Eastern Macedonia, and Thraki). Three species are described as new to science: Messordanaes Salata, Georgiadis & Borowiec, sp. nov. (Cyclades: Serifos), Messorkardamenae Salata & Borowiec, sp. nov. (Dodecanese: Kos, Nisyros, Rhodes, and Tilos), and Messorveneris Salata, Georgiadis & Borowiec, sp. nov. (Cyclades: Milos). The fifth member of the complex, Messorcreticus Borowiec & Salata, 2019, maintains its status of Cretan endemic.

The Intranidal Myrmecophiles of the Maltese Islands with Notes on Messor Nests as Repositories of Biodiversity.

The intranidal myrmecophilous arthropod fauna of the Maltese Islands is reviewed. Thirty species from nine orders are found to be obligate myrmecophiles, of which four species are recorded from the Maltese archipelago for the first time: Phrurolithus sp. (Araneae: Phrurolithidae), Pogonolaelaps canestrinii (Berlese, 1904), Gymnolaelaps messor Joharchi, Halliday, Saboori & Kamali, 2011 and G. myrmecophilus (Berlese, 1892) (Mesostigmata: Laelapidae). Phrurolithus also represents the first record of the family Phrurolithidae in Malta. Notes on the biology and local distribution of each species are provided, including ant-myrmecophile associations, of which two appear to be previously unknown: the occurrence of Smynthurodes betae Westwood, 1849 (Hemiptera: Aphididae) in the nest of Plagiolepis pygmaea (Latreille, 1798) and Phrurolithus in the nest of Pheidole pallidula (Nylander, 1849). Fourteen additional species are found to be either only occasionally myrmecophilic, accidental ant-guests or potentially myrmecophilous, the latter remaining ambiguous due to a lack of knowledge of their biology. Of these, the family Caeculidae (Arachnida: Trombidiformes) represents a new record for the Maltese Islands, on the basis of Microcaeculus sp. occurring in a nest of Camponotus barbaricus Emery, 1905. Preliminary results indicate that Messor nests may be repositories of considerable myrmecophile diversity, with the most unique symbionts.

A striking color variation is detected in Poneratestacea Emery, 1895 (Hymenoptera, Formicidae) across its Western Palaearctic geographic range.

In this paper, we provide numeric morphology-based evidence that the dark-colored Poneracoarctatavar.lucida Emery, 1898, formerly considered a synonym of P.coarctata (Latreille, 1802), is conspecific with the lighter-colored Poneratestacea Emery, 1895. Species hypotheses are developed via NC-PART clustering, combined with Partitioning Algorithm based on Recursive Thresholding (PART), and via PCA combined with gap statistics. We obtained our results from an extensive dataset from the 10 continuous morphometric traits measured on 165 workers belonging to 73 nest samples. Linear discriminant analysis (LDA) confirmed the grouping of hypotheses generated by exploratory analyses with 100% classification success when all ten morphometric traits were involved. The Anatolian Turkish black and the predominantly European yellow samples, did not separate based on their morphometric characteristics. These two color variations broadly overlap in their geographic range in Anatolian Turkey. The investigated type series of Poneracoarctatavar.lucida Emery, 1898 (collected from Kazakhstan) fell within the P.testacea cluster instead of P.coarctata and is also classified with high certainty as P.testacea by confirmatory LDA. Therefore, we propose the synonymy of Poneracoarctatavar.lucida Emery, 1898 with Poneratestacea Emery, 1895. As no other morphological differences than color patterns were detected between the "black" and "pale" P.testacea samples, we hold that these populations constitute geographically occurring color variations of the same species. Finally, our quantitative morphology-based results show that relying on color patterns is not a robust approach in identifying European Ponera samples, particularly in the east, but using multivariate analyses of morphometric traits is advised instead.

New and little-known ant species (Hymenoptera, Formicidae) from Bulgaria.

Background: Many faunistic studies on the myrmecofauna of Bulgaria have been carried out and about 180 ant species (Hymenoptera, Formicidae) from 43 genera and six subfamilies have been discovered as a result. Although the Bulgarian ant fauna is considered to be relatively well studied, the finding of unrecorded species continues, especially amongst the rare social parasites and the species with a more southern distribution in the Balkans. New information: The current study presents data on 11 ant species recorded for the first time in Bulgaria (Messorhellenius Agosti & Collingwood, 1987, M.mcarthuri Steiner et al., 2018, Crematogasterionia Forel, 1911, Monomoriummonomorium Bolton, 1987, Temnothoraxaeolius (Forel, 1911), T.cf.exilis(formdarii Forel, 1911), T.finzii (Menozzi, 1925), T.rogeri Emery, 1869, Tetramoriumcf.punicum, Plagiolepisxene Stärcke, 1936 and Lasiusreginae Faber, 1967), as well as new locality data on 15 rarely found species. Some of the species, such as Hypoponeraeduardi (Forel, 1894), Strumigenysargiola (Emery, 1869), Temnothoraxgraecus (Forel, 1911), Tetramoriumdiomedeum Emery, 1908, Camponotusionius Emery, 1920 and C.tergestinus Müller, 1921, have been known so far only from a single locality in Bulgaria.The dataset of all records presented in this work was published separately through Global Biodiversity Information Facility (GBIF, https://doi.org/10.15468/mngbzp).

An updated checklist of ants (Hymenoptera, Formicidae) of Bulgaria, after 130 years of research.

Background: The Bulgarian myrmecofauna is one of the richest in the Balkans. This is a result of both the physicogeographical and paleoecological features of the area, as well as relatively well-studied fauna. The earliest myrmecological paper on Bulgarian fauna, listing 54 species, was published 130 years ago. The publication was later followed by numerous new faunistic records and three comprehensive reviews that significantly widened knowledge on the ant diversity from this country. The most recent checklist was released 12 years ago and considered 163 ant species from 40 genera. New information: This work provides an updated checklist of 195 ant species from 43 genera occurring in Bulgaria. Since the last Bulgarian catalogue of ants, 44 species have been added, while 24 species have been synonymised or excluded after critical analysis of the last taxonomic revisions. Additionally, we discuss the status and distribution of 12 species described from Bulgaria, 23 species considered endemic and subendemic for this country, 19 species with conservation status and four non-native species.

Ant genus Strongylognathus (Hymenoptera, Formicidae) in Bulgaria: a preliminary review.

BACKGROUND: Strongylognathus Mayr, 1853 is a Palaearctic genus, comprising 25 ant species and one subspecies, all permanent social parasites, infesting colonies of various species of Tetramorium Mayr, 1855. They have patchy distribution throughout their areas and most of them are very rare and listed as vulnerable.The taxonomy of the Strongylognathus huberi group needs thorough revision and the results presented below can be considered as preliminary. NEW INFORMATION: Four species of the socially parasitic ant genus Strongylognathus (S. karawajewi Pisarski, 1966, S. huberi dalmaticus Baroni Urbani, 1969, S. afer Emery, 1884 and S. italicus Finzi, 1924) are recorded for the first time from Bulgaria and, together with the previously-known S. testaceus and S. bulgaricus stat. rev., their total number reaches six. The taxonomic position and geographic distribution of all species are discussed and a Key for their identification, based on worker caste, is compiled.

Aphaenogasterillyrica, a new species from the mountains of the Balkan Peninsula (Hymenoptera, Formicidae).

Aphaenogasterillyrica sp. nov., a member of the A.subterranea species group, is described from Dinaric Alps of Slovenia and Croatia, from Golesnica Mt. in north Macedonia, Osogovo-Belasica Massif of southwestern Bulgaria, and from Kerkini Mts. of Greek Macedonia. It is characterised by large body size, moderately sculptured head, elevated mesonotum, and long propodeal spines. Its habitat preferences are discussed. A key to the Aphaenogastergraeca complex is provided.

New data on the geographical distribution and host utilization of the entomopathogenic fungus Myrmicinosporidium durum.

Entomopathogenic Myrmicinosporidium durum Hölldobler, 1933, a fungus known to exploit several ant species, is reported for the first time in five countries: Bulgaria, the Czech Republic, Romania, Slovakia, and Turkey. The discovery of the fungus in Anatolia significantly widens its known distribution. In addition, this fungal parasite was found to utilize two hitherto unknown host species: Tetramorium sp. D (sensu Schlick-Steiner et al. 2006 ) and Tetramorium sp. E (sensu Schlick- Steiner et al. 2006 ). According to the new data, M. durum seems to be more common in Europe than previously thought, while its host range is considerably larger. In the present paper, data on its currently known distribution and host preference are discussed.

Catalogue of the ants (Hymenoptera, Formicidae) of Bulgaria.

The present catalogue of the ants (Hymenoptera, Formicidae) of Bulgaria is made on a base of critical reconsideration of literature (covering the period from 1892 till 2009 and part of 2010) as well as on examination of the authors' and several museum's collections. A lot of data were omitted in the previous Bulgarian monograph on ants, lots of new data were recently added and many important additions and alterations were made due to taxonomic revisions of Eurasian Formicidae during the last three decades. Two new species are reported for the country [Temnothorax graecus (Forel, 1911) and Temnothorax cf. korbi (Emery, 1924)].This catalogue contains a list of 163 ant species belonging to 40 genera of 6 subfamilies now known from Bulgaria. Synonyms and information on the previously reported names in relevant publications are given. Known localities of the species are grouped by geographic regions. Maps with concrete localities or regions for each species were prepared. The conservation status of 13 ant species is given as they are included in IUCN Red List of Threatened Species and Bulgarian Biodiversity Act. In comparison with adjacent Balkan regions the ant fauna of Bulgaria is quite rich and its core is composed of South European elements.