Évolution d'Une Virose A Fuseaux dans la Nymphe et l'Adulte de Melolontha Melolontha [Col. Melolonthidae

Abstract

SUMMARYEvolution of spheroidosis in the pupa and imago of Melolontha melolontha [Col. Melolonthidae]The pathogenesis of a spheroidosis in larvae, pupae and imagos of a Coleopter Melolontha melolontha L. has been studied by curves of mortality and of development after infection and, histologically, in consideration of tissue changes of pupae and imagos.The virus infection stops the metamorphosis before the pupal and the imaginal moults according to the developmental stage of the insect at the time of infection.It is shown the occurence and the development of two types of cytoplasmic inclusions in pupae and imagos as also that the infection at a given time is necessary in order that the development of lesions occurs during pupal and imaginai stages. As in larvae, the fat body of pupae and imagos displays the most serious lesions. Virus inclusions are also localized in peritracheolar cells and in the connective sheath of gonads of infected imagos. The occurence of such lesions in periganglionnar cells of matured larvae and prepupae is considered to be connected with the stop of normal development of the insect during pupal and imaginai moults.