Somogyi Múzeumok Közleményei 17/B. - Természettudományi tanulmányok (2006)

Majer, József and Krčmar, Stjepan: Geographical distribution of Tabanids (Diptera: Tabanidae) of the Drava river along the Somogy County (Hungary), the Koprivničko-križevačka and one part Virovitičko-podravska County (Croatia) - Somogy-megye (Magyarország), Kapronca- és részben Verőce-megye (Horvátország) Dráva-menti bögölyeinek földrajzi előfordulása

196 JÓZSEF MAJER and STJEPAN KRCMAR The collecting of the samples of the species Atylotus flavoguttatus extend the known area of spreading of this species in Europe. Moreover the collected sample includes the species Hybomitra ucrainica new for the Hungarian fauna (MAJER & KRĈMAR, 1998). It has been recorded on one locality on the Hungarian banks of river Drava. Ну. ucrainica is a little known species of the genus Hybomitra and thus its distribution area is still not fully recognized. This species was described recently on the material collected in Ukraine, and specimens of this species were also recorded in Turkey, Moldavia and Rumania around the Danube delta (OLSUFJEV, 1977; PARVU & GIRAY, 1984). Several specimens have also been determined in Eastern Austria (MALLY, 1986). In Croatia this species were mostly collected in habitats overgrown with reeds along the Karaŝica, Danube, Drava, Sava and Neretva rivers (KRĈMAR et al. 2003). The distribution of this species is rather unknown because it is frequently mistaken for a very similar species Hybomitra ciureai (Mally, 1986). The collected sample also includes several Mediterranean species: Chrysops flavipes, Chrysops italicus, Tabanus exclusus, Tabanus spectabilis, and Tabanus spodopterus which are represented by a smaller number of specimens (MAJER, 1983, 1985, 2001; TÓTH, 2000, 2003). The specimens of these Mediterranean species were mostly collected in the Bares Juniper Woodland in Hungary (MAJER, 1983, 1985, 2001; TÓTH, 2000, 2003). However, this Mediterranean species not found presently either there or in other parts along of the Drava river. Larvae of the most determined Mediterranean species live in the soils with high percentage of salt and their imagos occasionally reach some salty habitats in Central Europe (CHVALA et ai. 1972). This is the most probable explanation why several Mediterranean species were also collected along river of Drava which, by the way, should be no exception. Since the northern border of distribution of these Mediterranean species is on the territories of Austria, Czech Republic, Slovakia and Hungary (CHVALA et ai. 1972). In addition to these Mediterranean species, in Croatia distribution area for the species Chrysops parallelogrammus mostly follows river valley of Drava. As regards that specimens of Ch. parallelogrammus were collected in Croatia only on the stations that are in the immediate vicinity of the river Drava. The majority of the species determined along the Drava River belong to the Boreal - Eurasian species (27). Apart from the Boreal - Eurasian species the collected sample also included horse flies belonging to Mediterranean group (6), South European group (5), Afro-Eurasian arid group (3,) and European group (1) species (Table 1). From the point of view of medical or veterinary entomology, attention should be paid to the females of the most abundant species of horse flies, such as Tabanus bromius and Haematopota pluvialis regarding the fact that they are the vectors of spiroplasmas (LE GOFF et al. 1991; VAZZEILLE-FALCOZ et al. 1997). Furthermore, the species T. bromius and Hae. pluvialis are also the most abundant species in the some flood areas in Croatian sections of the river Danube (KRĈMAR, 2004). Unlike from T. bromius and Hae. pluvialis the majority of species collected in this study were of sparse or low abundance (Table 1). This study was extended to cover both sides of river Drava and because of greatly contribute to the knowledge of the fauna of horse flies and also to the knowledge of the distribution of particular species in this part of Europe. The qualitative structure of the determined 42 species indicates a great wealth of the horsefly fauna in this marginal part of the Pannonian Plain, especially in the view of the fact that the horsefly fauna of this part of Hungary makes up 59,01% of the fauna of horse flies in Hungary. The flight period of Tabanids mostly depend on the seasonal meteorological variability that occurs periodically from one year to another and have a significant influence on the duration of tabánid flight activity. These 42 tabánid species are certainly not the final number of species on the study area, since only during this research we have identified 4 species of Tabanids that were not recorded during previous studies. We presume that some other species of Tabanids are present in the region as well, because Tabanids can fly rather far. This assumption suggests the necessity to continue with systematic entomological research. The present knowledge is not the final status of horse flies fauna on the study area. We also can expect some species along of river Drava that are already known in neighbouring areas.