Methylation-sensitive representational difference analysis (MS-RDA) is suitable for screening and identification of specific and low abundances genomic DNA methylation. It has been applied in many researches on mammal disease occurrence and plant developmental mechanism

but no application was reported in insects.In this study

we developed a MS-RDA method for insects

which was improved from DNA extraction

restriction enzyme digestion

amplicon preparation

and competitive hybridization. The method was further applied successfully in Sogatella furcifera (Horvath)

an important rice pest in China. Four differentially methylated DNA sequences related with female and male were obtained. Three of them had been accepted by GenBank

the accession numbers were JX847621

JX624161

JX472453

respectively. Three of them were not found homologous sequences by BLAST and should be belonging to the new genes with functions unknown. Meanwhile

two differentially methylated DNA sequences related with long and short wing were obtained. Their accession numbers of GenBank were JX514031、JX472454

respectively. They were found highly similar with the 18S ribosomal or 28S ribosomal RNA gene sequences of many kinds of animals by homology analysis

therefore ribosomal RNA gene methylation maybe play some roles on wing dimorphism of S. furcifera.