Parasitoid wasps use a variety of mechanisms to alter their host's physiology to the benefit of the developing endoparasite inside the host larva. Association of certain wasps with viruses and virus-like particles (VLPs) that contribute to their success in parasitism is one of the fascinating evolutionary adaptations conferring active or passive protection for the endoparasite from the host immune system. Venturia canescens has been shown to produce VLPs that provide protection for the developing parasitoid egg inside the host, Ephestia kuehniella. Here, we report on the presence of a novel small RNA-containing virus from V. canescens, designated as VcSRV, occurring in the ovaries of the wasp. The virus particles are found together with VcVLPs in the lumen of the calyx region of the ovaries and are injected together with the egg and VcVLPs into E kuehniella larvae where they enter hemocytes. Alignment of the RNA-dependent RNA polymerase gene of VcSRV indicates that the virus most likely belongs to the recently described genus Iflavirus. [copyright] 2004 Elsevier Ltd. All rights reserved Ephestia kuehniella (Pyralidae) : Host Venturia canescens (Ichneumonidae) : Parasite Biochemistry; Reproduction; Reproductive system; Gonad; Parasites diseases and disorders; Parasites; Insect parasites; Hosts; Insect hosts Ephestia kuehniella; Hymenopteran parasites; Parasite oviposition transferral of novel RNA-containing viral like particles; Venturia canescens Venturia canescens; Proteins; Ovarian occurrence & oviposition transfer to lepidopteran host; Novel RNA-containing virus like particle presence; Ovary; Lepidopteran hosts; Ephestia kuehniella none