RELATIONSHIPS BETWEEN LIFE-HISTORIES OF LEAFHOPPERS (AUCHENORRHYNCHA-HEMIPTERA) AND THEIR HOST PLANTS (JUNCACEAE, CYPERACEAE, POACEAE)

The relationship between life histories of host plants and ecological characteristics of leafhoppers was studied on leafhopper assemblages f ound on 26 monocotyledonous plant species. The difference in disturban ce intensity between various habitats was reflected by differences in the life history syndromes of both plants (ruderal vs competitive and stress-tolerant) and leafhoppers. Leafhoppers on ruderal plants show a 'colonization syndrome', having higher dispersal ability, wider host plant ranges, larger geographic distribution, and more generations per year than species on competitive and stress-tolerant plants. This 'co lonization syndrome' evolved independently at least twice in leafhoppe rs, i.e., within Delphacidae and Cicadellidae. A gradient in nutrient concentrations, from extremely oligotrophic peatbogs to nutrient-rich littoral zone' vegetation, was reflected in the replacement of stress- tolerant by competitive plant species, but this change was not paralle lled by any difference in the ecological characteristics of their leaf hopper herbivores. There were no differences in host plant range; gene ration number, wing condition, and geographic range of leafhoppers ass ociated with their specialization to host plants from different famili es (Juncaceae, Cyperaceae, Poaceae) as well.