Hibernation induced biochemical changes in spotted stem borer <i>Chilo partellus</i>

Abstract

Spotted stem borer, Chilo partellus (Swinhoe) is one of the most destructive pests of sorghum and maize, and undergoes hibernation during harsh winters. Several aspects of diapause have been studied, however metabolic and biochemical processes underlying hibernation remain poorly understood in C. partellus. Present studies carried out during 2020–22 at ICAR-Indian Agricultural Research Institute, New Delhi deciphered the variations in nutritional biochemicals, digestive and stress enzymes, cryoprotectants in the hibernation and in non-hibernating larvae and pupae of C. partellus. These studies revealed that the total lipids and proteins were significantly greater during pre- hibernation and hibernation, and sugars were greater in non-hibernation larvae. Glycogen content was greater in pre- hibernation, and sorbitol, trehalose and glucitol contents consistently increased from pre-hibernation to hibernation stages in comparison to non-hibernation larvae of C. partellus. Total sugar and sorbitol contents decreased, while total protein, trehalose and glucitol increased, in post-hibernation than the non-hibernation pupae of C. partellus. Activities of ascorbic acid, lipid peroxidation, total antioxidant, catalase and superoxide dismutase were significantly greater during hibernation followed by pre-hibernation as compared to non-hibernation larvae, while the reverse was the case with protease activity. Ascorbic acid, lipid peroxidation, total antioxidant and catalase activities were greater in post-hibernation as compared to non-hibernation pupae of C. partellus. However, glutathione S-transferase activity was greater in the non-hibernation larvae and pupae than the hibernation larvae and post-hibernation pupae of C. partellus. These findings can be useful to design newer management strategies keeping in view the weak links like the state of nutritional metabolism and oxidative stress tolerance due to diapause in C. partellus.