Molecular identification and DNA barcode screening of acaroid mites in ground flour dust

Molecular identification of acaroid mites is difficult because of the scarcity of molecular data in GenBank. Here, acaroid mites collected from ground flour dust in Xi'an, China, were preliminarily morphologically classified/grouped. Universal primers were then designed to amplify and screen suitable DNA barcodes for identifying these mites. Sixty mite samples were morphologically classified into six groups. Groups 1-2 were identified to Dermatophagoides farinae and Tyrophagus putrescentiae, while Groups 3-6 were not identified to the species level. ITS2 exhibited higher efficiency in molecular identification in comparison with COI, 12S, and 16S. Groups 1-6 were identified as D. farinae, T. putrescentiae, Suidasia nesbitti, Chortoglyphus arcuatus, Lepidoglyphus destructor, and Gohieria sp., respectively. The phylogenetic results were consistent with the morphological classification. Group 6 was further identified as G. fusca according to the morphology of the reproductive foramen. We conclude that the use of ITS2 and the availability of universal primers provide an ideal DNA barcode for molecular identification of acaroid mites. The use of multiple target genetic markers in conjunction with morphological approaches will improve the accuracy of Acaridida identification.