大斑芫菁滞育幼虫在滞育不同阶段体内糖类和醇类含量的变化

在以卵滞育的昆虫中昆虫滞育时的生理代谢特点已经得到了大量研究。本文对以末龄幼虫（5龄）滞育的大斑芫菁Mylabris phalerate（Pallas）在不同滞育阶段体内糖类和醇类代谢的特征进行了研究。结果表明： 滞育个体血淋巴中的海藻糖含量高于非滞育个体，且随滞育时间的加大逐渐升高，滞育5个月时达到最大值，为5.61 μmol/mL。糖原的含量随滞育的进程逐渐减少，滞育初期（0.5个月）为0.72 mg/mL，到滞育末期（5个月）时仅为0.1 mg/mL。滞育个体脂肪体中的海藻糖含量都高于非滞育个体，滞育1个月时为非滞育个体的3倍，至滞育末期时达非滞育个体的5倍，为2.5 μmol/g脂肪体。糖原含量总体变化趋势是随滞育时间的加大逐渐减少，滞育早期和中期都高于非滞育个体。在滞育过程中血淋巴积累的小分子多元醇主要为甘油，其次是山梨醇；而在脂肪体中主要为甘油，其次是甘露醇，少量积累山梨醇：表明大斑芫菁滞育幼虫主要积累的是海藻糖和一些小分子多元醇。滞育幼虫在准备滞育时储备了大量糖原，这些糖原可能为滞育期间海藻糖、山梨醇和甘油的代谢提供了原料。

Change of trehalose, glycogen and polyol contents of the diapausing larvae of Mylabris phalerata ( Pallas ) ( Coleoptera: Meloidae ) at different diapausing stages

Blister beetle, Mylabris phalerata (Pallas) (Coleoptera: Meloidae), natural enemy of Chondracris rosea rosea (De Geer) (Orthoptera: Acridiidae) and important Chinese medicine material, has important economic significance. In this research, influence of diapause duration on trehalose, glycogen and polyol metabolism of the diapausing larvae of M. phalerata was examined. The results indicated that trehalose content in diapause larvae haemolymph, higher than non-diapausing larvae, was increased with the extension of the diapause duration: the maximal was 5.61 μmol/mL, which appeared in haemolymph of larvae diapaused for 5 months. During the diapause, glycogen content showed linear decrease: glycogen content was 0.72 mg/mL early in 0.5 month of diapause, but only 0.1 mg/mL at the end of diapause (5 months). Trehalose content in fat body in diapausing larvae was higher than in non-diapausing larvae, which was three times as high as that in non-diapausing larvae in one month of diapause, and five times as high asthat in non-diapausing larvae in 5 months of diapause (2.5 μmol/g fat body). Glycogen content were decreasing during the diapause: in the early and middle period of diapause, glycogen content in fat body of the diapausing larvae was higher than in non-diapause larvae. Polyol in the haemolymph of the diapausing larvae was mainly glycerol, next was sorbitol; but in fat body was mainly glycerol, next sorbitol and a little mannitol. These suggested that diapausing larvae accumulated trehalose and some polyol, but not glycogen. The content of glycogen decreased with the development of diapause. Thus glycogen may offer carbon source for producing trehalose, sorbitol, or glycerol.