Hyposoter didymator / HdIV

Hyposoter didymator

As this species is very common in Mediterranean zones, it is able to noticeably regulate noctuid pests populations in this region.

Hyposoter didymator is a solitary endoparasitoid wasp.

1. Female lays only one egg within a young caterpillar
2. After 2 days, the egg hatches  
3. Larva lives on host tissues,
4. When its development is achieved, mature larva goes out of the host caterpillar (which dies then) and weaves its cocoon to turn into a pupa.

Complete development lasts about 2 weeks at 25° C.

Parasitized caterpillars phenotype is characterized by a decreasing diet, decreasing weight growth and stopping their development at the fourth stage.
 Viral particles of the associated polydnavirus are produced within the parasitoid ovaries, then injected within a caterpillar during oviposition.

HdIV polydnavirus

Discovered in the 70’, polydnaviruses (PDVs) are characterized by a genome composed of 15 to more than 100 circular dsDNA molecules.
PDVs are divided into Bracoviruses (BVs) associated to Braconid wasps and Ichnoviruses (IVs), associated to Ichneumonids.
PDVs are stably integrated into parasitoid genomes as proviruses and replicate only in the calyx cells nuclei. Structural genes are present within the wasp genome but not encapsidated.
Viral particles containing the segmented genome are stored in the oviducts and injected into the host hemocele by the females during oviposition.
Inside the Lepidoptera host, PDVs do not replicate but infect several tissues. PDV infection results in alterations in growth, development and metabolism of the parasitized caterpillar and in inhibition of the immune response.

Studied biological models

The team research focuses on the interactions between 3 Ichneumonoidea species and their Lepidoptera larvae hosts:

• Hyposoter didymator (Ichneumonidae; Campopleginae), which parasitizes several Noctuids, associated with an ichnovirus;
• Macrocentrus cingulum (Braconidae; Macrocentrinae), polyembryonic parasitoid of Ostrinia spp. larvae;
• Venturia canescens (Ichneumonidae; Campopleginae), which parasitizes Pyralidae larvae, associated with virus-like particles (VLPs).