Evidence for Reconsidering the Taxonomic Status of Closely Related Oligonychus Species in punicae Complex (Acari: Prostigmata: Tetranychidae)

Abstract

To elucidate the taxonomic problems in species delineation within the Oligonychus punicae complex (O. punicae, O. mangiferus, and O. vitis) (Acari: Prostigmata: Tetranychidae), we performed morphological and molecular investigations on mite samples, collected from different hosts/countries. Thirty-nine samples of punicae complex, collected from Egypt, Pakistan, and Saudi Arabia (SA), did not show any considerable morphological differences in females and males. All 39 samples of the punicae complex resembled the original description of O. punicae, while the claimed Mexican O. punicae was distinctively different based on male aedeagus. Molecularly, the low nucleotide diversity ranged from 0% to 2.1% (ITS2-rDNA) and 0% to 1% (COI-mtDNA), and was observed among various DNA sequences of the punicae complex from Egypt, India, Israel, Pakistan, and SA, confirming their identity as one species. The high genetic divergence ranged from 17.2% to 18.8% (ITS2) and 9.2% to 10.2% (COI), observed between the claimed Mexican O. punicae and all other sequences of the punicae complex, indicating that the Mexican sample do not belong to O. punicae. Basing our findings on both morphological and molecular data, we can conclude that O. mangiferus and O. vitis are synonymized with O. punicae. Additionally, this study reveals that the claimed Mexican O. punicae needs to be re-identified.

Molecular-Based Taxonomic Inferences of Some Spider Mite Species of the Genus Oligonychus Berlese (Acari, Prostigmata, Tetranychidae)

“…Mite samples of O. coniferarum , O. dactyloni , O. punicae , O. pratensis , O. tylus , and O. washingtoniae were collected from SA and morphologically identified by Alatawi and Kamran [ 23 ]; Mushtaq, Kamran, and Alatawi [ 21 ]; and Mushtaq, Kamran, Saleh, and Alatawi [ 7 ]. The samples received from Mexico (SVN: 53, O. perseae Tuttle et al), USA (SVN: 40, O. pratensis ), and Yemen (SVN: 49 and 50, O. afrasiaticus ) were initially identified/labelled and sent to us by our colleagues [ 24 , 25 ] at our request.…”

“…In the genus Oligonychus Berlese (Acari, Prostigmata, Tetranychidae), morphological-based differentiation among species always depends on the characterization of the key trait of male aedeagus [ 1 , 2 , 3 ]; however, in the subdivision of Oligonychus into subgenera and groups/subgroups, the characterization of both male and female is compulsory [ 3 ]. Indeed, exact species identification in Oligonychus is usually a challenge because of the minute differences in aedeagus; limited diagnostic traits in females; and the presence of various species complexes, e.g., pratensis complex and punicae complex [ 1 , 2 , 3 , 4 , 5 , 6 , 7 ]. Moreover, the key diagnostic trait of the aedeagus becomes unreliable if males are not mounted accurately in their lateral positions, or are either described briefly without illustrations or with insufficient morphological details [ 8 , 9 ].…”

“…DNA-based methods include DNA sequences, e.g., nuclear and mitochondrial genes. The mitochondrial cytochrome c oxidase subunit I (COI) gene has been used extensively in identifying organisms, including mites [ 7 , 12 , 13 , 14 , 15 ]. The internal transcribed spacers (ITS1 and ITS2) regions of nuclear ribosomal DNA have also been applied accurately for the identification or confirmation of closely related species in the family Tetranychidae Donnadieu [ 7 , 13 , 14 , 16 , 17 ].…”

“…The mitochondrial cytochrome c oxidase subunit I (COI) gene has been used extensively in identifying organisms, including mites [ 7 , 12 , 13 , 14 , 15 ]. The internal transcribed spacers (ITS1 and ITS2) regions of nuclear ribosomal DNA have also been applied accurately for the identification or confirmation of closely related species in the family Tetranychidae Donnadieu [ 7 , 13 , 14 , 16 , 17 ]. The combined use of morphological- and molecular-based methods for species delineation would greatly help resolve problems of synonymy and the misidentification of closely related tetranychid species [ 18 , 19 , 20 ].…”

“…The combined use of morphological- and molecular-based methods for species delineation would greatly help resolve problems of synonymy and the misidentification of closely related tetranychid species [ 18 , 19 , 20 ]. Recently, an integrative taxonomic study has successfully resolved the long-standing issue of the punicae species complex in the genus Oligonychus [ 7 ].…”