S. Mahunka szerk.: Folia Entomologica Hungarica 56. (Budapest, 1995)

1982). Several components of the vegetation structure (vegetation texture and architectural complexity) emerge from the literature as important contributors to variation in herbivore abundance, diversity, and life history. Vegetation texture includes several attributes: plant density (the distance between individuals of the same species), patch size (the geographical extent of the stand), and vegetation diversity (frequency and identity of nonhostplant individuals (Kareiva 1983). Individual plants may also vary in architectural complexity, involving two characteristics: plant size (the spread of plant tissue through different positions in space) and the variety of plant structures (number of plant parts, both in form and persistence (Southwood et al. 1979). These components of vegetation structure define together to a large extent the habitats of herbivorous insects. Variation in these components and interactions among them result in an array of habitat possibilities, each with different consequences for herbivorous insects. Trends have emerged in both plant diversity and structure (Southwood et al. 1979), and in the associated insect herbivore community, where species diversity, guild structure, niche breadth, morphological diversity and reproductive effort have been found to vary. Rushton et al. (1989) have reported that upland improved pastures have obviously different ground beetle and spider faunas from those of the unmanaged upland pastures and that management practices are reflected in the species assemblages of these invertebrates on improved pastures. Agricultural management in lowland areas was shown to affect the distribution of grassland weevil species. Luff & Eyre (1988) used ground beetles to monitor change in habitat with a land use change from agricultural to heath land. Acknowledgments - The study - the field work and the preparation of the paper was supported by a grant of the National Scientific Research Fund to Cs. Moskát (OTKA, No. 1/3 3188). I am indebt to L. Ádám for taking part in the field works. I am grateful for the comments and advice to Cs. Moskát, and for the revision of the English text to T. Fuisz. REFERENCES Capinera, J. L. & Schechrist, T. S. (1982): Grasshopper-host plant associations: response of grasshopper populations to cattle grazing intensity. - Can. Entomol. 114: 1055-1062. De Keer, R., Alderweireldt, M., Decleer, K., Seders, H. & Maelfait, J.-P. (1989): Horizontal distribution of the spider fauna of intensively grazed pastures under the influence of diurnal activity and grass height. -J. Appl. Entomol. 107: 455-473. Deltschev, C. & Kajak, A. (1974): Analysis of a sheep pasture ecosystem in the Pieniny mountains (the Carpathians). XVI. Effect of pasture management on the number and biomass of spiders (Araneae) in two climatic regions (the Pieniny and the Sredna Gora mountains). - Ekol. Pol. 22: 693-710. Duffey, E. (1962): A population study of spiders in limestone grassland. The field-layer fauna. - Oikos 13: 15-34. Fielding, D. J. & Brusven, M. A. (1993): Grasshopper (Orthoptera: Acrididae) community composition and ecological disturbance on southern Idaho rangeland. - Environ. Entomol. 22 (1): 71-81.