Abstract: Thrips (Insecta: Thysanoptera) are of a species-rich order with small size, which makes them hard to be identified quickly and accurately by traditional morphological identification methods. In this study, the mitochondrial cytochrome c oxidase subunit Ⅰ(COⅠ) genes of 25 thrips species common in China were amplified using DNA barcoding universal primers. The obtained partial COⅠ fragments (about 650 bp) were sequenced. The phylogenetic tree was established by a neighbor-joining (NJ) method. The intra- and inter-species genetic distances were calculated with MEGA version 4.0 software using the Kimura 2-Parameter model. The results indicated that the identification results based on the phylogenetic tree obtained was consistent with those based on morphological characteristics for the 25 thrips species. In these species, the lengths of intra-species branches were much shorter than those of the interspecies branches. Each branch corresponded to one species and all bootstrap values of the original divergence among different haplotypes within one species were 100%. The genetic distance between species for these 25 species was 102.1 times as high as the corresponding values within species (0.2757 vs. 0.0027). There was no overlap between inter- and intra- species genetic distances. The results suggest that the DNA barcoding based on partial COⅠ gene can provide rapid and accurate identification of these thrips species.

Key words: Thysanoptera, thrips, COⅠ gene, DNA barcoding, molecular identification, genetic distance, phylogenetic tree