DNA barcoding, species-specific PCR for the identification of three stored-product pest species of genus Palorus (Coleoptera: Tenebrionidae)

Flour beetles of the genus Palorus (Coleoptera: Tenebrionidae) are important secondary storage pests. Correct identification of these insects is urgently required for integrated pest management. However, traditional morphological classification methods cannot identify insect fragments or immature stages and require skilled taxonomists with training and experience. In this study, three Palorus species were distinguished with two molecular techniques; DNA barcoding and species-specific PCR based on the mitochondrial DNA cytochrome oxidase subunit I (COI) gene. Forty-nine individuals of Palorus subdepressus (Wollaston), Palorus ratzeburgi (Wissman) and Palorus cerylonoides (Pascoe) were collected from 19 different locations across rice processing factory, feed factory, flour mill and bulk storages China. The COI sequences were analyzed by K2P distances and neighbor-joining (NJ) tree for DNA barcoding. The results show that these three Palorus species can be successfully identified by DNA barcoding. For the species-specific PCR study, we designed specificity primer pairs for the three Palorus species and evaluated their sensitivity. The results showed that the three Palorus species can be identified by the species-specific PCR method. Our results indicated that the two techniques can be independently used to identify the Palorus species in China for integrated pest management and quarantine. This is the first time Palorus species have been identified using two molecular techniques and the P. ratzeburgi and P. cerylonoides data have filled a gap in BOLD and GenBank.