S. Mahunka szerk.: Folia Entomologica Hungarica 52. (Budapest, 1992)

steep. In the pioneer plant associations of these sites the soil is shallow, and the chemical-physical structure of the basic rock has the greatest influence on the soil. The study was carried out in the following plant associations (following the categorization of Jakucs 1981): (A) Open dolomitic grassland (Sesseli leucospermo-Festucetum pallentis) having a southern exposure. Plant cover is 30-70% dominant grass species is the Festuca pollens. (B) Ecotone zone between the open and the closed grasslands. (C) Open dolomitic steppe-meadow (Chrysopogono-Caricetum humilis), having a southwestern exposure. Cover of plants is 60-80% dominant plant species is the Carex humilis. (D) . Closed dolomitic grassland (Festuco pal lenti-Br omet urn pannoniéi), having a northern exposure. The vegetation is totally closed, dominant grass is the Bromus pannonicus. The study site (C) was marked out on the Kutya Hill, and the others were situated on the Odvas Hill. The edges of the sample sites followed the boundaries of the natural vegetation. The size of the study sites (A) and (B) was about 200 x 200 m, about 300 x 500 m of the site (C), and 10 x 100 m of the site (D) Methods Based on the instructions of Southwood (1978) a linetransect-type method was chosen for collecting data on grasshoppers. This consists of visual observation along aim wide transect with the same constant speed of walking (300m/lh). All of the individuals identified by eyes along a transect were recorded. The duration of a sampling procedure at a site was 10 minutes. This procedure seemed to be sufficient for the majority of species, but in cases of a few groups identification was possible only for the genus level (Glyptobothrus, Omocestus, and Euchortippus). Data collection was made fortnightly on 4 sites from the 10th of August to the 17th of October in 1989. One visit in a week was carried out for each plots, and data were collected in the interval from 10 a.m. to 3 p.m. The Shannon-Weaver index was applied for the computation of diversity: H =-2pi In pi where H = diversity, pi = relative frequency of species i, In = natural logarithm. For the comparison of insect communities referring to different plant associations the Bray-Curtis index (1957) was applied: C

n =2Jn / (An +Bn) where C

n = Bray-Curtis index, J

n = number of individuals of common species of two associations, An = number of individuals of association A, Bn = number of individuals of association B.