In this work we present a complex of 12 parasitoid species which act in the Aphis fabae colonies installed on Helianthus annuus, Beta vulgaris, Papaver rhoeas, Phaseolus vulgaris, Centaurea scabiosa and Arctium minus Bernh plants. In this complex, 4 species are primary parasitoids and the other species act as secondary or tertiary parasitoids. We accomplish a synecological analysis of the parasitoid species and we elucidate the relations among them. BR Animals and man. Control. Parasites diseases and disorders. Parasites. Insect parasites. Hosts. Insect hosts. Land zones. Palaearctic region. Eurasia. Europe. Hymenoptera (Insecta): Parasite; Aphis fabae (Aphidoidea): Host, Parasite; Lysiphlebus ambiguus (Aphidiidae): Host, Parasite; Lysiphlebus fabarum (Aphidiidae): Host, Parasite; Lysiphlebus melandriicola (Aphidiidae): Host, Parasite; Praon dorsale (Aphidiidae): Host, Parasite. Aphis fabae: Biological control, pathology, Hymenopteran parasites, Lysiphlebus ambiguus, Lysiphlebus fabarum, Lysiphlebus melandriicola, Praon dorsale, Plant hosts, Cultivated crops, Romania; Hymenoptera: Hymenopteran hosts, Lysiphlebus ambiguus, Hyperparasitism, Lysiphlebus fabarum, Lysiphlebus melandriicola, Praon dorsale, Romania; Lysiphlebus ambiguus, Lysiphlebus fabarum, Lysiphlebus melandriicola, Praon dorsale: Biological control, pathology, Hymenopteran parasites, Hyperparasitism, in hemipteran hosts, Hemipteran hosts, Aphis fabae, Romania. ST Animalia, Arthropoda, Insecta, Hemiptera, Homoptera, Sternorrhyncha, Aphidoidea; Animalia, Arthropoda, Insecta, Hymenoptera, Apocrita, Terebrantia, Ichneumonoidea, Aphidiidae. Arthropods; Hymenopterans; Insects; Invertebrates; True Bugs. none2006