Developmental changes caused by metyrapone and azadirachtin in Spodoptera littoralis (Boisd.) (Lep, Noctuidae) and Galleria mellonella (L.) (Lep, Pyralidae)

Larvae of Spodoptera littoralis and Galleria mellonella reared on standard laboratory food were used in experiments with metyrapone and azadirachtin. Metyrapone in S. littoralis caused high elevation of metabolic rate which r esulted in a significant increase of body-mass. This phenomenon was associa ted with precocious transformation to pupal stage. The same results were ob tained after application of azadirachtin or neem oil. Restriction of reprod uction was also observed in S. littoralis. Both these compounds influenced body pigmentation: the treated larvae was light green or light gray. Synthe sis of melanin was inhibited. In Galleria mellonella, the effect was not as prominent.