Suppressive Effects of Gossypol on the Spodoptera littoralis (Lepidoptera: Noctuidae) Reproduction and Enzymatic Properties

Introduction: Fecundity (egg laying) and fertility (egg hatching) are important components of insect reproduction. Gossypol has been reported to be an active anti-reproductive inhibitor by reducing or completely impairing fecundity and fertility in various animal species.Methods: Tested sublethal dose (LC25) of gossypol effects on the fourth instar larvae reproduction parameters and detoxifying enzyme activities of the cotton leaf worm, Spodoptera littoralis (Lepidoptera: Noctuidae) compared with control was evaluated.Results: Gossypol showed toxicity against the second and the fourth instars larvae of S. littoralis after 72 hours of treatment; the LC50 values were 162.56 and 296.30 mg (ai)/Kg of artificial diet, respectively. Gossypol significantly suppressed oviposition and adult emergence, as well as prolonged the pre-oviposition period. According to the results, the highest fecundity inhibition more than 43% was observed in mating of treated females (TF) with treated males (TM) in addition to the highest fertility inhibition of 33%. Gossypol significantly reduced the activities of the detoxification enzymes including glutathione S-transferase (GST), lactic dehydrogenase (LDH), and protein content.Conclusion: Overall, the results showed that the exposure of larvae by the sublethal dose (LC25) of gossypol negatively affected the egg laying and egg hatching as well as reduced the activities of the detoxification enzymes in the cotton leaf worm. These findings may pioneer new approaches to control this pest.

Suppressive Effects of Gossypol on the Spodoptera littoralis (Lepidoptera: Noctuidae) Reproduction and Enzymatic Properties Keywords:

detoxification enzymes , fecundity , Fertility , Gossypol , Glutathione S-Transferase , Lactic dehydrogenase , Oviposition