| The brown planthopper Nilaparvata lugens and small brown planthopper Laodelphax striatellus are important pests on rice and often cause significant economic losses to rice production.The small brown planthopper and brown planthopper have two types of wings:long and short wings.Wing differentiation is an adaptive strategy evolved by insects to face different environmental conditions.Understanding and clarifying the regulation mechanism of the wing differentiation of planthoppers will be beneficial to the prediction and prevention of the pesr occurrence.In this paper,the wing diferentiated individuals appearing in the wing type selecting process of the brown planthopper and the small brown planthopper were used as the materials.The fertility,adult life span,nymph mortality,wing length and weight of the long and short winged offsprings from the same parents were measured.The results would expect to provide a reference for the elucidation of the genetic regulation mechanism of wing differentiation of rice planthoppers.The main results obtained by the study are as follows:In the small brown planthoppers,the long-winged rate increased from 66%to 86%when the selection for the long-winged strain was performed for one to three generations,and the short-winged rate increased from 58%to 76%during the three generations of selection for the short-winged strain.In the brown planthoppers,the long-wing rate increased from 47%to 59%during three generations of selection for the long-wnged strain,and the short-winged rate was high(92%to 99%)during the three generations of selection for the short-winged strain.Both the short-and long-winged offspring were found in the first to third generation of selection for the long-or short-winged strain in the brown planthoppers and small brown planthoppers.The biological characteristics,such as the reproduction,nymphal survival rate,adult wing type,sex ratio,were measured in the short-and long-winged small brown planthoppers descend from the same parents in the selected strain for the long-winged.The results showed that the adult longevity,body weight and their nymphal survival of the short-winged individuals were as similar as these from the long-winged individuals.The fecundity of the short-winged was higher than that of the longed-winged in the first generation of selection,but it became the same in the second generation of selection.In the short-winged strain,the long-winged individuals showed the similar fecundity,adult longevity,nymphal survival as the short-winged individuals.But the body weight of male adults descend from the short-winged was higher than that from the long-winged.In the selected long-winged strain of the brown planthoppers,the adult longevity and female adult body weight of the short-winged individuals were the same as the long-winged individuals.But the fecundity,nymphal survival and body weight of male adults were different.There was no difference in the fecundity between logn-winged and long-winged individuals in the first generation of selection,but it was lower in the short-winged than that of the long-winged in the second generation.The male body weight of the long-winged individuals was heavier than the short-winged individuals.In the selection of the short-winged strain of the brown planthoppers,the long-winged individuals had the identical longevity and adult body weight to the short-winged individuals.But the fecundity of the long-winged individuals was lower than the short-winged in the first generation of selection,whereas it became similar in the second generation of selection.There was no difference in the survival rate of nymphs from the long-winged and short-winged individuals in first generation of selection,but in second generation of selection,the survival of the long-winged was higher than that of the short-winged.In summary,the biological characteristics of the short-and long-winged individuals from the same parents were almost similar.The genetic backgrounds play a key role in the determination of wing morphs in rice planthoppers. |
