S. Mahunka szerk.: Folia Entomologica Hungarica 57. (Budapest, 1996)

Fig. 2/A. Histogram of the species numbers of the oak forest. — Fig. 2/B. Histogram of the species numbers of the different forest layers. — Abbreviations: C = canopy layer, S = shrub layer, Y = young forest, M = mixed forest, P = pure forest agile in their parasitoid etc. activity than the braconids? A bionomical enigma interesting for a special research. The number of species (NS) of the braconid communities was the highest in mixed oak forest at both study sites (NS (Csobánka) = 28, NS (Gödöllő) = 20) (Fig. 2/A). The values of the number of species (NS) of the braconid communities of the different forest layers were the highest in the shrub layer of the pure oak forest (NS = 18), the canopy (NS = 15) and shrub (NS = 19) layer of mixed oak forest at Csobánka. However, the number of species (NS) of the communities was the highest in the canopy of the young oak forest (NS = 13) and the shrub of the mixed oak forest (NS = 15) at Gödöllő (Fig. 2/B.). The Shannon-Wiener diversity indices showed slight difference between the braconid communities of the same layer of forest stands in the two study sites (Csobánka and Gödöllő). The difference among the diversity values of communities in the canopy layers of the mixed oak forest (H = 2.152), pure oak forest (H = 2.634) and young oak forest (2.144) was not significant in the study site of Gödöllő. However, the values of diversity indices of communities in the same layer of forest stands were decreasing from the mixed oak forest (H = 2.943) through the pure oak forest (H = 2.611) toward young oak forest stand (H = 1933) at Csobánka (Fig. 3/A). The situation of diversity values of Fig. 3/A. Diversity values of the braconid communities in the canopy layers of the different oak forest types. — Fig. 3/B. Diversity of the braconid communities in the shrub layers of the different oak forest types. — Abbreviations: C = canopy layer, M = mixed forest, P = pure forest, S = shrub layer