Diapause-induced shift in the content of major carbohydrates in Chilo partellus (Swinhoe)

Abstract

Although several aspects like diapause determining factors, population structure, reproductive physiology, and genetics of diapause have been investigated, there is no clarity on carbohydrate energetics during larval diapause in Chilo partellus (Swinhoe). Present studies revealed significant variation between the nondiapausing and diapausing C. partellus for total carbohydrates, glycogen, sorbitol, and trehalose contents in different body parts, life stages, and for body parts × life stages interaction. Total carbohydrate content started declining, while sorbitol and trehalose increased in all the body parts as the C. partellus larvae progressed from prediapausing to diapausing state. However, glycogen content spiked in all the body parts at prediapausing stage, which then declined during diapause. Among the body parts, total carbohydrate content was significantly greater in the hemolymph as compared to other body parts of both larvae and pupae of C. partellus. Glycogen content was significantly greater in the larval fat bodies and pupal hemolymph as compared to their other body parts. In diapausing larvae, sorbitol and trehalose were greater in the integument than in other body parts. Furthermore, there was spike in trehalose and decrease in sorbitol in all the body parts of pupae from diapausing than those from nondiapausing larvae. These findings suggest that the diapause alterate and/or fluctuate major carbohydrates in different body parts of both larvae and pupae of C. partellus. This information will be helpful in better understanding the diapause energetics and overwintering metabolic cryoprotection in insects.