DNA Barcoding: A Reliable Method for the Identification of Thrips Species (Thysanoptera, Thripidae) Collected on Sticky Traps in Onion Fields

Abstract

Several thrips species (Insecta, Thysanoptera) are globally known as important crop pests and vectors of viral diseases, but their identification is difficult because of their small body size and inconspicuous morphological differences. Sequencing variation in the mitochondrial cytochrome c oxidase I (COI) region has been proven to be useful for the identification of species of many groups of insect pests. Here, DNA barcoding has been used to identify thrips species collected with the use of sticky traps placed in an open onion field. A total of 238 thrips specimens were analyzed, 151 of which could be identified to species and 27 to genera belonging to the family Thripidae. Fifty-one specimens could not be assigned to any genus, with the closest BLAST match in the GenBank queries being below 98%, whilst six specimens were not recognized as Thysanoptera. The results indicate that, although there are a few pest thrips species not yet barcoded, most of the species that may cause damage to crops in Europe are represented in GenBank and other databases, enabling correct identification. Additionally, DNA barcoding can be considered a valuable alternative to the classic morphology method for identification of major thrips species.

Thelytokous Reproduction of Onion Thrips, Thrips tabaci Lindeman 1889, Infesting Welsh Onion and Genetic Variation among Their Subpopulations

“…In recent years, the study of the mitochondrial regions of DNA including COI, using molecular biology, has proved useful in understanding some biological aspects of onion thrips populations [20]. The phylogenetic analysis of COI sequences supported the thelytokous reproductive mode of T. tabaci infesting Welsh onion.…”

Olive Production Threatened by a Resurgent Pest Liothrips oleae (Costa, 1857) (Thysanoptera: Phlaeothripidae) in Southern Italy

“…The maximum likelihood phylogenetic tree based on mitochondrial gene revealed that L. oleae is well separated from all other Liothrips species ( Figure 3 ). As recently described, Marullo et al [ 44 ] also successfully distinguished some thrips species of the same genera based on mt- COI gene sequences. Furthermore, COI gene sequencing possibly identifies unknown specimens by comparing their COI sequence, and it has been used for identification purposes in projects known as species barcoding.…”

First Field Record of the Tropical Red-Banded Thrips Selenothrips rubrocinctus (Thripidae: Panchaetothripinae) in Europe

“…Two different COI haplotypes were detected for adult and larval specimens collected from different host plants in different municipalities. Marullo et al [55], recently demonstrated that DNA barcoding is a reliable tool for identifying genetic differences within the same thrips population. Our results revealed some genetic variation due to the presence of two haplotypes collected in the same location (Trescore Cremasco, where more specimens were collected and barcoded) and on the same host plant (C. betulus).…”