Accumulation and utilization of food reserves in diapause-destined pallid emperor moth, Cirina forda (westwood)

Abstract

Diapause is a complex life history strategy aimed at tolerating or circumventing stress in insects. It is accompanied by alterations in the food reserve levels to cope with the energy demand of this life stage. In the pallid emperor moth (Cirina forda), little is known about the patterns of accumulation and utilization of food reserves before and during diapause, respectively. The accumulation and utilization of food reserves in the haemolymph and the whole body of diapause-destined larvae and diapausing pupae of Cirina forda were progressively compared using photometry and HPLC. The quantity of glucose, total carbohydrate, fats, protein, and amino acids measured were taken as indices of food reserve accumulation and utilization by the immature stages of the insect in this study. Data collated were analyzed using Analysis of Variance (ANOVA), and the means were separated using Fisher's Least Significance Difference (LSD). The results showed progressive accumulation of glucose from 46.20 to 105.06 mg/100 g, total carbohydrates from 175.39 to 212.54 mg/100 g, lipids from 440.49 to 641.57 mg/100 g, and protein from 306.04 to 378.83 mg/100 g in the haemolymph of diapause-destined larvae. The reserves decreased progressively (72.1%, 60.3%, 5.7%, and 6.9%) in diapausing pupae. Total amino acids increased by 2.8%, while 61.1% of amino acids in the whole pupae increased significantly (P<0.05). The study concluded that C. forda accumulates food reserves in preparation for diapause, and reserves decline as they are probably utilized during diapause development.