褐飞虱、白背飞虱的种内和种间效应

在室内条件下研究了褐飞虱，白背飞虱在3种类型水稻稻苗上的种内密度效应和种间互作效应，结果表明：在6－24头／盆若虫和2－6对／盆成虫的接虫密度范围内，褐飞虱，白背飞虱的种内密度效应均较弱，其中尤以褐飞虱的种内密度效应更弱，种内密度效应与水稻品种有关，在秀水11和协优9308上，白背飞虱的种内密度效应相对较强；褐飞虱在浙852和协优9308上表现一定的密度效应；褐飞虱和白背飞虱共存时种间在互利关系，其中尤以对白背飞虱有利，主要表现为两种飞虱的若虫存活率，成虫短翅率，单雌每天产卵量和后代虫孵化率在混合饲养时比一种飞虱单独饲养时均有不同程度的提高。

Intra-and interspecificrelationship of Nilaparvata lugens(stl) and Sogatella furcifera (Horváth) onvarious rice varieties

The intra|and inter|specific relationship of Nilaparvata lugens (stl) and Sogatella furcifera (Horvath) on three rice varieties, Z852, XS11 and XY9308, were studied in the laboratory. The density|dependent effects of S. furcifera and N. lugens were weak on the three rice varieties at nymphal densities ranging from 6 to 24 or adult densities ranging from 2 to 6 pairs per cage. The density|dependent effects of N. lugens were weaker than those of S. furcifera. There were various adverse effects of intra specific crowding of the two species on the three varieties. The density|dependent effect of S. furcifera were stronger on XS11 and XY9308 than that on Z852; The density|dependent effect of N. lugens were stronger on Z852 and XY9308 than that on XS11.The interspecific interactions between S. furcifera and N. lugens were beneficial to each other. The nymphal survival rate, brachypter rate, fecundity, and hatchibility of each species in the mixed culturing of the two species were significantly higher than those in separated culturing.