Generalist hymenopteran parasitoids of the leaf-miner Chromatomyia fuscula(Zett.) (Dipt.: Agromyzidae)

In southeastern Norway, by the last week of June (1992), 48% of Chromatomyi a fuscula emerged, based on the number of mines collected from Hordeum vulg are leaves. Among the parasitoids Diglyphus begini was the dominant species , but Cirrospilus vittatus and Neochrysocharis aratus also emerged in signi ficant numbers, During June and July, N. aratus was the dominant species in the Ist and 2nd leaves, but D. begini was dominant in the 4th to 6th leave s. C. vittatus and Cyrtogaster vulgaris affected all larvae of the leaf-min er fly, living on various leaves. In central Norway, 48% of C. fuscula also emerged. C, vulgaris and D. begini were the dominant parasitoids and C. vi ttatus was also found. C. fuscula has no specialist parasitoids, Adults of the generalist parasitoids of the leaf-miners always search for different h osts. In investigation of the parasitoid complex of a lepidopteran leaf-min er, Phyllocnistis labyrinthella (living in Populus tremula leaves at the ed ge of the examined barley field), three shared parasitoids (C, vittatus, Pn igalio soemius and Pnigalio pectinicornis) were found. The complex network of host plant-phytophagous insect-insect parasitoid-facultative hyperparasi toid relationship is discussed.