›› 2008, Vol. 51 ›› Issue (11): 1103-1112.

• RESEARCH PAPERS •     Next Articles

Comparisons of levels of crude fat,soluble sugars,and free amino acids in offsprings of the immigrant and non-immigrant populations of the brown planthopper, Nilaparvata lugens (Stål) (Homoptera: Delphacidae), under insecticide stress

YIN Jian-Li   

  • Online:2008-11-20 Published:2008-11-20

Abstract: To understand the biochemical difference between immigrant and non-immigrant Nilaparvata lugens offspring populations, we compared the changes in soluble sugar and crude fat contents in the 3rd and 5th instar nymphs and adults of the offsprings from immigrant and non-immigrant N. lugens, and free amino acid content in immigrant adults and their offspring adults on two rice varieties (TN1 and Xieyou 963) under insecticide stress. The biochemical substances were associated with insect origin (immigrant or non-immigrant), developmental stage, and insecticide type and insecticide concentration. Soluble sugar contents in the 3rd and 5th instar nymphs and adults of the offsprings that developed from the plants treated with insecticides and control (untreated) plants of TN1 for immigrant N. lugens were significantly higher than those for non-immigrant N. lugens. In contrast to soluble sugar content, crude fat content in the 3rd and 5th instar nymphs and adults of the offsprings that developed from the plants treated with insecticides and control plants of TN1 for immigrant N. lugens was significantly lower than that for non-immigrant N. lugens. For Xieyou 963, soluble sugar content in the 3rd and 5th instar nymphs showed the same tendency as TN1. Crude fat content in adults developed from control plants for immigrants was significantly higher than that for non-immigrant populations, and that in the 3rd and 5th instar nymphs did not show a significant difference between immigrant and non-immigrant N. lugens. Crude fat content in the 5th instar nymphs and adults which developed from the rice plants treated with insecticides for immigrant populations was significantly higher than that for non-immigrant. ANOVA results also demonstrated that as for changes in soluble sugar and crude fat contents, there were significant interactions between insect origin and insecticide type, insect origin and insecticide concentration, and insecticide type and insecticide concentration. For the two rice varieties, free amino acid content in immigrant adults was significantly lower than that in their offspring adults. Amino acid content in adults that developed from TN1 plants treated with triazophos was significantly higher than with deltamethrin and imidacloprid, while  in adults that developed from Xieyou 963 plants treated with deltamethrin and imidacloprid it was significantly higher than that with triazophos. The present findings have important significance for understanding the mechanism of insecticide-induced resurgence of the N. lugens.

Key words: Nilaparvata lugens, immigrant population, non-immigrant population, crude fat, soluble sugar, amino acid