Physiological symptoms induced by ecdysone agonist methoxyfenozide on the contton leafwqrm, Spodoptera lilttoralis (BOISD.) [electronic resource].

Includes reference.

Newly ecdysed fourth instar larvae of the cotton leafworm, Spodoptera littoralis (Boisd.) were treated with LC₅₀ of ecdysone agonist methoxyfenozide, to provide better insights into physiological symptoms and aspects induced by it as a mimic to the 20-hydroxyecdysone (20-E) action Larvae Ingest methoxylenozide died wilhin 2-3 days, and being trapped within their excuvae. They stopped feeding shortly before ecdysis. Treatment neither accelerated ecdysis nor ceased feeding, as soon as the larvae ingest such 20-E mimic, The continuous binding of the compound to the ecdysteroid receptors of S. littorlis larvae increased the titre of enzymes regulated by 20-E during the experimental time (3 days). Chitinase and phenoloxidase were activated after 6 and 12 hr from methoxylenozide administration, respectively. The compound had no effect on chitin production, but endocuticle chitin degradation during moulting might be depressed as illustrated by the presence of higher amount of N-acelylglucosamine in control larvae than mothoxyfenozide treated. It is suggested that methoxyfenozide might induces a precocious moult by initiating moulting cycle, but its main toxic effect is due to the fact that its level remains high during moulting and don't decrease for allowing other hormones necessary lor successful mouilting to be released.

Summary in arabic.

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