Western European Populations of the Ichneumonid Wasp Hyposoter didymator Belong to a Single Taxon

Abstract

Hyposoter didymator (Hymenoptera, Ichneumonidae) is a generalist solitary endoparasitoid of noctuid larvae. In the present work, we tested whether populations of H. didymator were divided in several genetically distinct taxa as described for many other generalist parasitoid species, and whether differences in H. didymator parasitism rates were explained by the insect host species and/or by the plant on which these hosts were feeding on. The genetic analysis of natural populations collected in different regions in France and Spain on seven different insect hosts and seven different host plants (775 individuals) showed that H. didymator populations belong to a unique single taxon. However, H. didymator seems to be somewhat specialized. Indeed, in the fields it more often parasitized Helicoverpa armigera compared to the other host species collected in the present work. Also, H. didymator parasitism rates in field conditions and semi-field experimental studies were dependent on the host plants on which H. armigera larvae are feeding. Still, H. didymator can occur occasionally on non-preferred noctuid species. One hypothesis explaining the ability of H. didymator to switch hosts in natura could be related to fluctuating densities of the preferred host over the year; this strategy would allow the parasitoid to avoid seasonal population collapses.

The Parasitoid Hyposoter didymator Can Transmit a Broad Host Range Baculovirus in a Two Host System

“…There were no significant differences between S. littoralis and S. exigua, well down in comparison with H. armigera. According to Frayssinet et al [64], H. didymator parasitizes more often on H. armigera although it can occasionally occur on non-preferred noctuids, which demonstrated that the parasitoid can switch hosts in nature due to fluctuating densities of the preferred host over the year. Choice tests showed that infection with AcMNPV did not affect the host preference of the parasitoid.…”

Genomic architecture of endogenous ichnoviruses reveals distinct evolutionary pathways leading to virus domestication in parasitic wasps

“…Two species from the monophyletic subfamily Campopleginae [53,54] were chosen as target taxa for whole genome sequencing: Hyposoter didymator occurs in all Western Europe and mainly parasitizes Helicoverpa armigera [70] whereas Campoletis sonorensis occurs from North to South America and parasitizes several noctuid species [71].…”

Massive Somatic and Germline Chromosomal Integrations of Polydnaviruses in Lepidopterans

“…In the present study, we first apply the approach developed in Muller et al (2021) on the C. typhae / S. nonagrioides system to comprehensively characterize and quantify DNA circle integration of yet another PDV, the Hyposoter didymator IV (HdIV), in two tissues of parasitized fall armyworms ( Spodoptera frugiperda , Lepidoptera, Noctuidae). Hyposoter didymator is a Campopleginae wasp (Ichneumonidae) showing a marked host preference for Helicoverpa armigera in the wild, but it is able to parasitize a large variety of other noctuid moths, including S. frugiperda ( Frayssinet et al 2019 ). Our results further underline the striking similarities in integration patterns between IVs and BVs, despite that these domesticated endogenous viruses are derived from viruses belonging to different families.…”