The Hemiptera of Two Sown Calcareous Grasslands. I. Colonization and Early Succession

Abstract

(1) Hemiptera were sampled from two contrasting grasslands sown in April 1973 on a chalk soil which had previously grown cereals. Four replicates of the treatments were arranged in a randomized block design. Pitfall traps were used for 4 months after sowing, and vacuum net sampling late in 1973 and throughout 1974 and 1975. (2) The first colonists included typical opportunistic leafhoppers, seventeen species being recorded in 1973. The Heteroptera were varied and included many species not characteristic of calcareous grassland. (3) The most abundant Heteroptera during the whole sampling period were Nabis ferus, Notostira elongate, Trigonotylus ruficornis and Lygus rugulipennis. The last species declined in abundance from 1973 to 1975 and is not a typical grassland species. (4) The most numerous Auchenorhyncha were Arthaldeuspascuellus, which accounted for nearly half the individuals recorded, Javesella pellucida, Psammotettix cephalotes, Cicadula persimilis and Zyginidia scutellaris. A. pascuellus, Javesella pellucida and three other species declined in abundance from 1974 to 1975. (5) Although fifty species of Auchenorhyncha and forty of Heteroptera were recorded, many occurred as single specimens and equitability of both faunas was low. More species of Auchenorhyncha were recorded in 1975 than in 1974 and diversity of the faunal samples was consistently higher. Similar trends were not noted in the Heteroptera. (6) The results are discussed with reference to the establishment and management of species-rich grasslands for nature conservation.