Tóth Sándor: A Bakony természettudományi kutatásának eredményei 25. - A Bakonyvidék zengőlégy faunája (Diptera, Syrphidae) (Zirc, 2001)

HOVERFLY FAUNA OF THE BAKONY REGION (SUMMARY)

MISKOLCZI 1987). The concept of this method which was elaborated for dragonflies is to determine the number of 10 x 10 km quadrates in which the species was collected of all the possible places of collection (that means that not all the 1052 quadrates should be taken but only those which actually represent at least one place of collection, in the case of hoverflies this number is 485). In the assessment of the hoverfly fauna of Hungary the following categories are given: I. Sporadic (1-7 quadrates), II. Rare (8-24 quadrats), III. Less frequent (22-63 quadrates), IV Frequent (64-189 quadrates), V Very frequent (number of 10* 10 km UTM quadrates exceeds 190). Abundance values are summarized in a table (Table III.) and in the chapter dealing with faunistical data, when giving a brief characterization of each species. Quantitative composition of the hoverfly fauna As a result of research work covering the whole mountains and which have been carried out for a longer time a relatively clear picture could be given on the quantitative composition of the hoverfly fauna. A compilation (Table II.) reveals that individual numbers of the species are in a very broad range, between 1 and 5461. Nevertheless, unusually high values do not occur. Sphaerophoria scripta is the most abundant, showing a dominance of 7.7%. Episyrphus balteatus is the second (6.8%), and Eristalis tenax is the third (6.7%). The participation of only 25 taxa exceeds 1%, amounting to 7.3% of all the species but to 63.3% of all the specimens (Fig 7.) UTM grid mapping of the syrpid fauna In order to reveal and utilize the information hidden in the occurrence of living organisms mapping of places of occurrence can play an important role. That is why zoologists frequently make use of maps of different type in order to demonstrate the pecularities in the occurrence of their taxon. The author - following György Dévai's relevant work - has completed the UTM grid maps of Hungarian species. The UTM map which describes the places of occurrence of hoverflies in Hungary in 10 x 10 km quadrates (Fig 14.) relatively well depicts how well hover flies are investigated in Hungary. The recorded, exactly 2100 places of occurrence are situated in 485 quadrates. It is obvious that the 10x10 km quadrat size is less suitable for analyzing the fauna of a small geographical unit by grid map in details. Therefore in the Bakony Mts. already in the middle 1980' we started to work with smaller quadrates (TÓTH 1987). In the practical mapping primarily 2.5x2.5 km subgrid proved to work well. Places of occurrence of some species are shown on the presently available computer-aided version of the UTM grid maps of the Bakony (Fig 15.) The biggest part of the book is the chapter which gives the brief characterization of the species and faunistic data. Luckily itemized baseline data could be presented, creating a hoverfly database of the mountains which can be used later on for several purposes. Data which are given at the characterization of the species are partially also available in a table format (Table III.). It contains occurrence of the species by small geographical units, number of plant taxa visited, the characteristic feeding habits, and when possible, the habitat, data on swarming, some ecological factors, individual number, value of dominance and category of frequency.