NEW DATA ON THE MYRMECOFAUNA (FORMICIDAE, HYMENOPTERA) OF DELIBLATSKA

Myrmecofauna of the Federal Republic of Yugoslavia, as well as of other territories formerly constituting Yugosalvia is still insufficiently investigated. Such investigations are important because these territories belong to the Balkan Peninsula which is very rich in myrmecofauna. This is confirmed by the results of Ago s t i and Coli i n g woo d (1987) who registered 319 species in the myrmecofauna of the Balkans. Among them 72 species are registered in other Balkan countries, but still are not found in Yugoslavia. These authors also mentioned 42 species which could be expected in the myrmecofauna of the Balkans. Z i v 0 j i nov i c (1950) and V 0 g r i n (1955) registered certain number of ant species among other insect species in some regions of Yugoslavia. Exclusively myrmecological data are found in few myrmecological papers (Z i m mer man n 1934; Pet r 0 v 1986, 1992,1993; Petrov and Mesaros 1988; Karaman 1998; K a ram an et al. 1998; Coil i n g woo d and Petr 0 v 1999). Up to date, Ago s t i and Coli in g woo d (1987) reported 171 species of ants (Formicidae) for the myrmecofauna of former Yugoslavia. Pet r 0 v and Coil i n g woo d (1992) registered 210 species. The most recent knowledge including published and unpublished data, shows that the present number of known ant species of former Yugoslavia is 234 (Petrov upubl. data). Concerning the Federal Republic of Yugoslavia, the total number of known ant species is 160 (Petrov, unpubl. data). Deliblatska pescara (Deliblato Sands) does not belong to the Balkan Peninsula, but it is an adjacent region. It is situated in Serbia, about 70 km northeast from Belgrade and represents a part of the Pannonian Plain. It has an oval shape in NW-SE direction, and covers about 25.000 hectares. Its altitude ranges from 75 m a.s.l. on the southeast part, near the river Danube (Dubovac), up to 193 m a.s.l. on the northwest part (Pluc).

Z i v 0 j i nov i c (1950) and V 0 g r i n (1955) registered certain number of ant species among other insect species in some regions of Yugoslavia.
Exclusively myrmecological data are found in few myrmecological papers (Z i m mer man n 1934; Pet r 0 v 1986, 1992,1993;Petrov and Mesaros 1988;Karaman 1998;K a ram an et al. 1998; Coil i n g woo d and Petr 0 v 1999).
Up to date, Ago s t i and Coli in g woo d (1987) reported 171 species of ants (Formicidae) for the myrmecofauna of former Yugoslavia.Pet r 0 v and Coil i n g woo d (1992) registered 210 species.The most recent knowledge including published and unpublished data, shows that the present number of known ant species of former Yugoslavia is 234 (Petrov upubl. data).Concerning the Federal Republic of Yugoslavia, the total number of known ant species is 160 (Petrov, unpubl. data).
Deliblatska pescara (Deliblato Sands) does not belong to the Balkan Peninsula, but it is an adjacent region.It is situated in Serbia, about 70 km northeast from Belgrade and represents a part of the Pannonian Plain.It has an oval shape in NW-SE direction, and covers about 25.000 hectares.Its altitude ranges from 75 m a.s.l. on the southeast part, near the river Danube (Dubovac), up to 193 m a.s.l. on the northwest part (Pluc).
Deliblato Sands is of dune character.Dunes extend in NW-SE direction too.They are different in height (2-4 m up to 20-30 m) and slopes.Between them there are wider or narrower, deeper or shallower channels.
Deliblato Sands is characterized by many peculiarities concerning the soil (sandy, dry), climate (big diurnal and annual fluctuation of temperature) and quantity and arrangement of rain fall during the year, which are different from those in the surrounding region.
Steppe, pasture grounds, swamp and forest habitats can be found in Deiblato Sands.Desert and semidesert habitats are present too.But due to the natural succession and artificial afforestation, in order to bind the drifting sand, desert and semidesert habitats are small in area and rare at present.
Pet r 0 v (1994) reported 32 species of ants for Deliblato Sands.This author did not find C. herculeanus and P. pygmaea, but in his collection, which was checked by Dr. C. A. Collingwood (Skipton, U. K, 1991), Camponotus ligniperdus and Plagiolepis vindobonensis were registered.Since the collection of Gradojevic could not be checked, and he had not mention the author(s) who identified his specimens of ants, C. herculeanus and P. pygmaea might, in fact, be C. ligniperdus and P. vindobonensis.Petrov and Collingwood (1993) described a new species (Formica balcanina) which belongs to the Formica cinerea group and which replaces F. cinerea on the Balkan Peninsula.The holotype was taken from Rosijana (Deliblato Sands, July 15, 1987.).This species was also registered in Rumania (M ark 0 1997) but probably lives in the southern Hungary, as well.
Examining the remaining material collected by using pitfall traps in one pinetree forest at the southeast part of Deliblato Sands, near the village Dubovac, and at the locality Cardak (southern part of Deliblato Sands), 14 more species were registered now (Table 1).Among these species, Leptothorax racovitzai Bondroit is one of 42 expected species in the myrmecofcuna of the Balkan Peninsula (Agosti and Collingwood 1987) and this is the first record of that species in the myrmecofauna of the Balkans.
Thirty two species mentioned by Pet r 0 v (1994), together with 14 species registered in the presented list and, if we accept, Camponotus herculeanus and Plagiolepis pygmaea mentioned by G r ado j e vic (1963) make the total of 48 ant species known for Deliblato Sands so far.
The number of 48 ant species of Deliblto Sands should not be considered as a definitive yet.Pet r 0 v (1994) mentioned 2 species: Dolichoderus quadripnctatus (Latreille) and Camponotus ligniperdus (Latreille) which had not been found, but which may be expected.C. ligniperdushas was registered now (Table 1), but some of Messor species should be expected too.' As the most characteristic ant species for Deliblato Sands Pet r 0 v (1994) pointed out Cataglyphis aensecens.Up till now, in the Federal Republic of Yugoslavia, it was registered in Deliblato Sands (G r ado j e vic ! 963,det.as Myrmecocistus cursor, Pet r 0 v 1986a, det.as Cataglyphis cursor aenescens), and Metohija (C 0 II i n g woo d, pers.comm.).It was, also registered in Croatia (Z i m mer man n 1934, Petrov 1987, upub!. data), Rumania (Paraschivescu 1967), Hungary (G a II e 1972) and Bulgaria (A tan ass 0 v andDlussky 1992).
This ant inhabits warm and dry semidesert and desert habitats.The society of C. anescens is monoginous and relatively small consisting of several hundred up to about 2.500 workers (P e t r 0 v 1998).It is a diurnal individually searching ant reaching the maximum of activity in the warmest period of the year (July and August) and also in the warmest period of the day (noon and early afternoon) when the temperature of sand can reach 60°C (P e t r 0 v 1992a).During their foraging trips, workers leave the nest 10 to 12 times during the day, reaching the maximum distance of about 10 m from the nest and showing site fidelity (P e t r 0 v 1993).Tile diet of this ant species consists mostly of dead insects, but sometimes it behaves as a predator, attacking caterpillars c. r honeybees overloaded by pollen and exhausted by heat (P e '-r 0 v 1990).This ant belongs to the group of desert ants, and plays a significant role in poor semidesert and desert habitats of Deliblato Sands (P e t r 0 v 1998).
Since desert and semidesert habitats in Deliblato Sands are disappearing because of mentioned reasons (natural successions, artificial afforestation), this species seems to be an endangered species in the area.
Acnowledgements -I want to express my gratitude to Dr C. A. Collingwood (Skipton, U.K.) for checking species of my collection.Thanks are also due to Mrs. Pavelka Ciric, Inst. of Zoo!., Fac. of Bio!.Univ. of Belgrade for her help in translating the text.This research was supported by the Ministry for Science and Technology of the Republic of Serbia.