白背飞虱对不同抗虫性稻株糖类物质的利用

本文通过对白背飞虱Sogatella furcifeta Horvath在不同苗龄抗虫品种Rathu Hee nati(简称RHT)和感虫品种Taichung Native 1(简称TNl)稻株上的取食反应，对摄入食物中糖类的利用和体内葡糖苷酶的活性变化，以及对稻株含糖量的分析，初步探讨了白背飞虱对稻株糖类物质的利用。白背飞虱在抗虫、感虫品种上的取食均随稻株苗龄的增长而降低，沮不管品种的抗虫性如何，稻株内的总糖量却随稻株苗龄的增加而上升。高效液相色谱分析飞虱分泌的蜜露结果表明，在RHT上分泌的蜜露里，蔗糖和果糖的含量明显地低于在TNI上分泌的。由此推测白背飞虱从RHT稻株韧皮部中吸食的汁液较从TNI中的少，但利用率高。取食RHT后的白背飞虱，体内的葡糖苷酶活性明显地较取食TNl后的低，并与飞虱体重的变化呈正相关。在白背飞虱体内可能存在着两种独立的、可控制食物的摄入及摄入食物的消化和吸收的机制。

UTILIZATION OF SUGARS FROM SUSCEPTIBLE AND RESISTANT RICE VARIETIES BY THE WHITEBACKED PLANTHOPPER,SOGATELLA FURCIFERA(HORVATH)(HOMOPTERA:DELPHACIDAE)

Utilization of sugars by females of Sogatella furcifera (Horvath)(Homoptera: Delphacidae) from rice plants of different age groups of resistant Rathu Heenati (RHT) and susceptible Taichung Native 1 (TN1) was studied by measuring honeydew excretion, sugars in the honeydew, total sugar contents in rice bleeding sap, and changes of a-glucosidaSe activity in planthopper individuals. Insect feeding decreased with the increase of plant age of both RHT and TN1 varieties. Regardless of varietal susceptibility, total sugar content in rice bleeding sap increased with increase in plant age. Analysis of honeydew by high performance liquid chromato graphy (HPLC) revealed that quantities of sucrose and fructose were significantlytess in honeydew excreted on RHT than on TNI plants, indicating that S. furcifera ingested less but utilized well the phloem sap from RHT as compared with TN1.Glucosidase activity of S. furcifera after feeding on RHT was significantly lowerthan on TN1, and was positively correlated with changes in insect body weight,There may exist two independent mechanisms which control ingestion of food, and digestion and absorption of the ingested food in S. furcifera.