Heliothis virescens HYMENOPTERAN-PARASITES; Campoletis sonorensis; Parasite development viral associates, parasite ecdysteroid relationships Campoletis sonorensis HORMONES-; Ecdysteroid effect on viral associate during development; DEVELOPMENT-; Ecdysteroid effect on viral associate; ASSOCIATIONS-; Polydnavirus; Development significance, ecdysteroid relationships, lepidopteran host; LEPIDOPTERAN-HOSTS; Heliothis virescens; Parasite development viral associates, parasite ecdysteroid relationships During oviposltlon the endoparasitic wasp Campoletis sonorensis, introduces a polydnavirus into parasitized insects where viral gene expression is required for endoparasite survival. The polydnavirus is integrated into wasp chromosomal DNA and replicates only in the ovary. Ecdysteroids regulate the developmental expression of many insect genes and may regulate polydnavirus replication. Direct verification of viral replication was performed by dot blot hybridization and by amplffylng DNA sequences containing the viral integration site; this "junction" fragment cannot be amplified from integrated virus. Thoracic legations and in vitro ecdysterold treatments of wasp ovaries support the hypothesis that potydnavirus DNA replication is regulated by ecdysterold during parasite development. none