Mass fingerprint analysis of spider mites (Acari) by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry for rapid discrimination

RationaleDiscrimination of spider mite species is still performed using morphological information, although DNA and other biological approaches have been attempted for identification purposes. These techniques need much time, are expensive, and require specialist staff. As an alternative, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS) analysis is applied for rapid discrimination of spider mite species. MethodsSpider mites were analyzed using MALDI-TOFMS after extraction with 70% formic acid and acetonitrile. A single spider mite was also analyzed directly on double-sided carbon tape. A dendrogram was compiled from the MS data. ResultsEvolutionarily close and morphologically similar spider mites, the Kanzawa (Tetranychus kanzawai) and the two-spotted (T. urticae) spider mites, as well as three other related species of spider mites, could be discriminated by mass fingerprints. Although female adults were mainly used in this report, male adults and nymphs showed almost the same mass fingerprints and were not considered to affect discrimination capability. A single spider mite on double-sided carbon tape was analyzed directly by MALDI-TOFMS. ConclusionsSpider mites could be analyzed directly by MALDI-TOFMS, with evolutionarily and morphologically closely related spider mites showing different mass fingerprints, allowing for their identification. Copyright (c) 2016 John Wiley & Sons, Ltd.