INFLUENCE OF PARASITISM BY GLYPTAPANTELES LIPARIDIS (HYM, BRACONIDAE)ON THE HEMOLYMPH CARBOHYDRATE AND GLYCOGEN-CONTENT OF ITS HOST LARVA,LYMANTRIA-DISPAR (LEP, LYMANTRIIDAE)

Parasitism of the gregarious endoparasitic braconid, Glyptapanteles li paridis, reduced markedly the haemolymph trehalose level of its host l arva, Lymantria dispar, when the parasitoid larvae had reached their f inal endophageous second instar. The extent of the trehalose decrease was dependent on the time of parasitization and therefore on the host stage in which the second instar parasitoids developed. The haemolymph glucose content amounted to 5-10% of the trehalose level during the f eeding period of unparasitized larvae and only rose before moulting. T he level was significantly reduced in hosts at the end of the endophag eous development of the parasitoid larvae as well as in hosts which co ntained parasitoid larvae moulting from the first to the second instar . Only in newly moulted third instar hosts parasitized during premoult to the second instar a markedly lower glycogen content was found than in unparasitized gypsy moth larvae. On the other hand, the mean glyco gen level of final fifth midinstar hosts was significantly elevated co mpared to unparasitized larvae, when they were parasitized one stage l ater, during the premoult period to the third instar. The number of pa rasitoids per host, however, did not significantly influence the host' s carbohydrate level.