Changes in Antioxidant Enzymes During the Development of the Cotton Leafworm, Spodoptera littoralis (Boisd.) (Lepidoptera: Noctuidae)

Abstract

Herbivorous insect pests are continuously suffering reactive oxygen species (ROS) from either endogenous or exogenous challenges and they possess an antioxidant system responsible for protecting insect tissues during its development. The present work aims to offer a comprehensive view of antioxidant activity of the destructive pest, the cotton leaf worm, Spodoptera littoralis (Boisd.). The level of four antioxidant enzymes namely, Catalase (CAT), Phenoloxidase (PO), Peroxidase (POX) and Glutathione-S-transferase (GST) have been assessed throughout the insect developmental stages. Generally, the late larval stages hold most of the antioxidant activity in all tested enzymes while the adult showed the least ones. Catalase was completely absent during egg stage while both PO and POX showed a similar trend of activity. The overall results showed a stage-specific antioxidant enzyme activities and we concluded that S. littoralis possess an efficient antioxidant enzyme system which able to withstand oxidative challenges and overcome oxidative stress threat. This study is an essential step in elucidating how antioxidant system develops with age in S. littoralis and eventually how can we make use of these information in future in insect control.