Abstract: Objective To establish a molecular method for identification of Blattisocius keegani based on ribosomal 18S rDNA gene sequences. Methods Storage samples were collected and isolated. Genomic DNA of a single mite was extracted on morphological identification basis. The COⅠand 18S rDNA gene sequences were obtained by PCR amplification,cloning and sequencing. Then the obtained sequences were aligned using Blast software,and 18S rDNA sequences of Blattisocius were retrieved from the GenBank. Multiple sequence alignment was done using the software Clustal(version 1. 83) with the known gene sequences. MEGA X software was used to analyze sequences,and the phylogenetic tree were constructed by neighbor-joining(NJ) method. Results The mites were identified as Blattisocius keegani based on COⅠ and morphological identification. The amplified sequences of the ten Blattisocius keegani were identical,showing A / T bias. The sequence homology of Blattisocius keegani with Blattisocius tarsalis and Blattisocius everti was 98. 73% and 98. 94%,respectively. Phylogenetic analysis based on 18S rDNA genes showed that the three mites were clustered into one branch. Conclusion We have successfully established a method for identifying Blattisocius keegani  on 18S rDNA sequences basis,which can be a foundation for accurate identification of Blattisocius keegani .

Key words: Blattisocius keegani , Molecular identification, Ribosomal 18S rDNA