DNA Barcoding and the Associated PhylAphidB@se Website for the Identification of European Aphids (Insecta: Hemiptera: Aphididae)

Abstract

Aphids constitute a diverse group of plant-feeding insects and are among the most important crop pests in temperate regions. Their morphological identification is time-consuming and requires specific knowledge, training and skills that may take years to acquire. We assessed the advantages and limits of DNA barcoding with the standard COI barcode fragment for the identification of European aphids. We constructed a large reference dataset of barcodes from 1020 specimens belonging to 274 species and 87 genera sampled throughout Europe and set up a database-driven website allowing species identification from query sequences.ResultsIn this unbiased sampling of the taxonomic diversity of European aphids, intraspecific divergence ranged from 0.0% to 3.9%, with a mean value of 0.29%, whereas mean congeneric divergence was 6.4%, ranging from 0.0% to 15%. Neighbor-joining analysis generated a tree in which most species clustered in distinct genetic units. Most of the species with undifferentiated or overlapping barcodes belonged to the genus Aphis or, to a lesser extent, the genera Brachycaudus, Dysaphis and Macrosiphum. The taxa involved were always morphologically similar or closely related and belonged to species groups known to present taxonomic difficulties.ConclusionsThese data confirm that COI barcoding is a useful identification tool for aphids. Barcode identification is straightforward and reliable for 80% of species, including some difficult to distinguish on the basis of morphological characters alone. Unsurprisingly, barcodes often failed to distinguish between species from groups for which classical taxonomy has also reached its limits, leading to endless revisions and discussions about species and subspecies definitions. In such cases, the development of an effective procedure for the accurate identification of aphid specimens continues to pose a difficult challenge.

Alfalfa leaf curl virus is transmitted by Aphis craccivora in a highly specific circulative manner

“…confirms previous work showing the difficulty to differentiate sub-species/populations within the very cosmopolitan A. craccivora group(Blackman and Eastop, 2000, Wang et al, 2011;Song et al, 2016;Coeur d'Acier et al, 2014). The EuphorbiaSA population was distinguished from other A. craccivora populations by its adaptation to spurges and by morphological differences.…”

Is phylogeography helpful for invasive species risk assessment? The case study of the bark beetle genus Dendroctonus

“…Finally, molecular tools allowing rapid and precise identification of intercepted organisms are increasingly available to plant biosecurity agencies (e.g. DNA barcoding; Armstrong and Ball , Coeur d'acier et al ). These tools allow the identification of the organisms and the identification of the lineage they belong to.…”

Buchnerahas changed flatmate but the repeated replacement of co-obligate symbionts is not associated with the ecological expansions of their aphid hosts

“…Aphids show considerable overlap in their morphological characters; consequently, their identification often relies on biological traits such as host-plant associations, which renders further investigations on the evolution of aphid life-history traits tautological (Coeur d’acier et al 2014). To avoid this bias, we complemented the morphological identifications of specimens with DNA-based species delimitation analyses.…”