Molecular, morphometric and digital automated identification of three Diaphorina species (Hemiptera: Liviidae)

Diaphorina is a species-rich genus, native to the tropics and subtropics of the Old World, particularly of more arid regions. One of the species, Diaphorina citri, is the economically most important pest of citrus. Diaphorina species are morphologically similar which makes their identification difficult. In this study, the accuracy of DNA barcoding, using mitochondrial cytochrome c oxidase subunit 1 (COI), geometric morphometrics of the forewing and digital image processing methods were tested for identification of the three Diaphorina species: D. chobauti, D. citri and D. zygophylli. Moreover, the published COI sequences of D. citri, D. communis and D. lycii obtained from Genbank were used for cluster analyses. DNA barcodes for D. chobauti and D. zygophylli are deposited in Genbank for the first time. The results of the molecular and geometric morphometric analyses are congruent and place D. chobauti as the sister taxon of the other Diaphorina species. The geometric morphometric analysis shows that in D. zygophylli the fore margin is slightly curved proximally and sharply bent distally, while in D. chobauti and D. citri it is straight proximally and weakly bent distally. The results of digital image processing show that the distribution of the dark pattern differs consistently in the three studied species.