DRY GRASSLANDS OF THE PANNONIAN LOWLAND - RELATION OF PHYSIOGNOMIC STRUCTURE AND FLORISTIC COMPOSITION TO CERTAIN INSECT GROUPS

Dry grasslands of the Pannonian lowland: loess, sand and alkali grassl ands and semi-dry grasslands of the hilly areas of the Aggtelek karst are compared. Floristical and life-form composition, physiognomical st ructure are considered in connection to two dominant phytophagous inse ct groups. The microclimatically sensible, but trophically not special ized Orthoptera-assemblages reflect mostly the physiognomical structur e of vegetation. They proved as good indicators of structural changes of vegetation based on quantitative relations of their well-defined li fe-form types. Because they are relatively unsensible on smaller-scale heterogeneities of their environment, their assemblages can be easily parallelized with the plant associations. Butterflies are often food- plant specialized, thus their resources regularly display a patchy pat tern. Hence, their meta-populations often cover a larger area which ca n be characterized by smaller spots of larval food-plants, stands of n ectar-sources and also by a landscape-scale structure of sigma-associa tions. Ir means thar they do not have a well-defined indicative value as a community, but ''individually'' several species can be regarded a s ''keystone species'' of large-scale spatial patterns of vegetation.