Biology and morphology of the parasitoidChelonus inanitus(Braconidae, Hymenoptera) and effects on the development of its hostSpodoptera littoralis(Noctuidae, Lepidoptera)

Abstract

Summary The solitary egg-larval parasitoids of the genus Chelonus have the unique effect of inducing in their lepidopterous hosts the precocious onset of metamorphosis and developmental arrest in the precocious prepupa. As a prerequisite to identifying the physiological and biochemical mechanisms underlying these developmental effects, we analyzed the morphology and various growth parameters in the course of development of Chelonus inanitus and studied the effect of this parasitoid on growth and development of its host Spodoptera littoralis. We show the first scanning electron microscopic study of the internal stages of an endoparasitic wasp from the embryo to the third instar. By including observations from microscopic and histological analyses we describe the different stages in the development of the anal vesicle and the formation of new segments and show that the anal vesicle has surface structures which were never described before. We also demonstrate that the head and mouthparts change entirely with...