Virus-like particles (MaVLP) have been discovered in the ovarial epithelial cells of the solitary. koinobiont, endoparasitoid, Microctonus aethiopoides Loan (Hymenoptera: Braconidae) introduced to New Zealand originally from Morocco to control the hicerne pest Sitona discoidetis Gyllenhal (Coleoptera: Curculionidae). MaVLP have been found in all females examined. It has been suggested, although not demonstrated, that like many other such VLP found in parasitoids, MaVLP might play a role in host iMMUnosuppression. Since another biotype of M. aethiopoides from Ireland has been proposed for introduction to control the white clover pest, Sitona lepidus Gyllenhal, in New Zealand, it was considered that females from this biotype warranted transmission electron microscope examination for VLP. No VLP were observed in ovarian tissues of specimens collected from three different locations in Ireland. Similarly, none were found in M. aethiopoides sourced from France, Wales, and Norway. These observations are discussed in relation to quarantine host specificity tests with the Irish biotype, which found that the host range of the Irish biotype is likely to be less extensive than that ofthe Moroccan biotype already in New Zealand. [copyright] 2005 Elsevier Inc. All rights reserved. none