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

This index the gives advantage whether consideration individual number, not only the species number. The Berger-Parker's dominance index (Berger and Parker 1972) was applied for showing of there is any dominant species in the community: D =n

ma

x/N dominance index, number of individuals of the most abundant total number of individuals. where D = nmax = species, N = Results During the study period 34 Orthoptera species were found, belonging to the following families: Acrididae (17 species), Tetrigidae (3 sp.), Oecanthidae (1 sp.), Ephippigeridae (1 s p.), Sagidae (1 sp.), Meconemidae (1 sp.), Phaneropteridae (2 sp.), and Tettigoniidae (8 sp.) (see Appendix for detailed list of species). The family of Acrididae contributes 53.1% to the total species number, and 91.6% to the total abundance. The species of the Acrididae family contributes relevantly to the total species number on each of the sites: open grassland (A): 95.1% ecotone zone (B): 96.9%, steppe meadow (C): 55.5%, closed grassland (D): 90.4% The distribution of these values is similar to the abundance ratios of the species of the Acrididae family: open grassland (A): 84.6% ecotone zone (B): 80.0% steppe meadow (C): 82.3% closed grassland (D): 71.4% Table 1. Structure parameters of Orthoptera communities on the dolomitic grasslands. (A) =open grassland, (B) = ecotone zone, (C) = steppe meadow, (D) = closed grassland (A) (B) (C) P) number of species 13 16 27 14 number of individuals 291 493 306 293 density (number of of individuals / visit) 36.82 61.62 36.75 35.50 Shannon-Weaver's diversity 1.057 1.369 2.259 0.902 % dominance of the most dominant genus 69 54 24 79 % dominance of the most dominant species 10 25 28 4