Morphology versus DNA barcoding: two sides of the same coin. A case study of Ceutorhynchus erysimi and C. contractus identification

Abstract

Genotyping of 2 well-known weevil species from the genus Ceutorhynchus (Coleoptera: Curculionidae) distributed in west Palearctic, C. erysimi and C. contractus, revealed phenotype versus genotype inconsistencies in a set of 56 specimens (25 C. erysimi and 31 C. contractus) collected from 25 locations in Serbia and Montenegro. An analysis of the mitochondrial cytochrome oxidase subunit I gene (COI), widely used as a barcoding region, and a nuclear gene, elongation factor-1α (EF-1α), revealed stable genetic divergence among these species. The average uncorrected pairwise distances for the COI and EF-1α genes were 3.8%, and 1.3%, respectively, indicating 2 genetically well-segregated species. However, the genetic data were not congruent with the phenotypic characteristics of the studied specimens. In the first place, C. erysimi genotypes were attached to specimens with phenotypic characteristics of C. contractus. Species-specific PCR-RFLP assays for the barcoding gene COI were applied for the molecular identification of 101 additional specimens of both morphospecies (33 C. erysimi and 68 C. contractus) and were found to confirm this incongruity. The discrepancy between the genetic and morphological data raises the question of the accuracy of using a barcoding approach, as it may result in misleading conclusions about the taxonomic position of the studied organism. Additionally, the typological species concept shows considerable weakness when genetic data are not supported with phenotypic characteristics as in case of asymmetric introgression, which may cause certain problems, especially in applied studies such as biological control programs in which the biological properties of the studied organisms are the main focus.

Implications of a phylogeographic approach for the selection of Ceutorhynchus assimilis as a potential biological control agent for Lepidium draba

“…The results presented here, confirm the proposal (Fumanal et al, 2005;Fumanal et al, 2004b) that Ceutorhynchus species (Laffin et al, 2005a) as confirmed by the divergence observed with the congeneric species used as outgroups. However, the level of divergence detected here is in the same order of magnitude as the one observed between two sister species, C. erysimi and C. contractus (Stepanović et al, 2015). Likewise, although the ABGD procedure tends to consider the three different lineages as a single species, the PTP analysis suggests that the Lepidium host race may potentially represent cryptic species or subspecies.…”

“…Despite numerous taxonomic revisions of the genus (Colonnelli, 1993;Colonnelli, 2004;Hoffman, 1954;Tempère and Péricart, 1989), taxonomical and nomenclatural issues represent the main constraints in studying this important weevil group, as highlighted by Stepanović et al (2015). In this context, although it was not the main aim of this study, we confirmed the distinction between the cabbage seedpod weevil, C. obstrictus (Marsham) [= C. assimilis (Paykull)], a serious European pest of canola or oil seed rape, which is invasive in North America (Dosdall and Mason, 2010;Laffin et al, 2005b), and C. assimilis [= C. pleurostigma].…”

Taxonomic integrative and phylogenetic identification of the first recorded Triatoma rubrofasciata in Zhangzhou, Fujian Province and Maoming, Guangdong Province, China

“…Moreover, molecular identification might be effectively applied to classify the immature stages of triatomines, as traditional taxonomic methods are difficult to use when distinguishing nymphs, especially considering the species complexes that exhibit large morphological and chromatic variation [28]. However, molecular identification will not take the place of morphological systematics because it relies on species definitions produced from morphological analyses [49]; hence, both approaches should be applied to provide effective, efficient and accurate species identifications [50, 51], and the integration of morphological and molecular methods is indicated for species recognition of T. rubrofasciata in future entomological surveys in China [6].…”

The intraspecific structure of the Yellow-spotted ringlet Erebia manto (Denis & Schiffermüller, [1775]), with special reference to the bubastis group: an integration of morphology, allozyme and mtDNA data (Lepidoptera, Nymphalidae, Satyrinae)

“…All populations sharing the Jura genital structure are found in haplotype clusters separated from cluster B by three mutational steps. Asymmetric introgression is regarded the most probable cause of this kind of discrepancies (Stephanović et al 2016). Given the considerable geographic distance, a recent involvement LG -Lake Geneva, LCo -Lake Constance, LM -Lake Maggiore, LC -Lake Como.…”