Molecular identification ofEpitrixpotato flea beetles (Coleoptera: Chrysomelidae) in Europe and North America

Abstract

Epitrix species (Coleoptera: Chrysomelidae) feed mostly on plants from the family Solanaceae and some of them are major pests of potato crops. All Epitrix species are morphologically highly similar, which makes them difficult to identify and limits their study and management. Identification of species is mostly based on the observation of the genitalia and requires a high level of expertise. Here, we propose a tool to reliably identify all developmental stages of the most economically important Epitrix species feeding on potato in Europe and North America (Epitrix cucumeris, Epitrix similaris, Epitrix tuberis, Epitrix subcrinita and Epitrix hirtipennis). We first sequenced two DNA markers (mitochondrial cytochrome c oxidase I (COI) and nuclear internal transcribed spacer 2 (ITS2)) to test their effectiveness in differentiating among six Epitrix species (126 specimens). Morphospecies of Epitrix were well-differentiated by both DNA barcodes and no mitochondrial introgression was detected. Then, we developed an RFLP-based diagnostic method and showed that unambiguous species discrimination can be achieved by using the sole restriction enzyme TaqI on COI polymerase chain reaction products. The tool proposed here should improve our knowledge about Epitrix species biology, distribution and host range, three capacities that are particularly important in the detection and management of these pest species. Specifically, this tool should help prevent the introduction of E. tuberis and E. subcrinita in Europe and limit the spread of the recently introduced E. cucumeris and E. similaris, with minimal disruption to Solanaceae trade.

Revision of Mandarella Duvivier from Taiwan, with a new species, new synonymies and identities of highly variable species (Insecta, Chrysomelidae, Galerucinae, Alticini)

“…Molecular approaches have been applied broadly in systematics of various insects and have fueled taxonomic debates about species recognition, especially when morphological characters are insufficient (Brown et al 2012, Kumar et al 2012; Lee et al 2013, Lees et al 2014, Park et al 2011, Tsai et al 2014). Sequences data from (COI)cytochrome oxidase subunit I , a small fragment of mitochondrial DNA, have been viewed as efficient markers in Chrysomelidae and have been exploited to resolve debates in identification (Germain et al 2013, Kubisz et al 2012, Lopes et al 2015) and elucidate species complex phylogenetics (Quinzin and Mardulyn 2014). Nie et al (2012) also used COI to clarify two closely related leaf beetles with color variation in elytra and pronota.…”

Molecular evidence supports the recognition ofEpitrix papaas a distinct species fromEpitrix similaris

“…Molecular data produced in this study served as a basis for correcting studies (Germain et al, 2013;Mouttet et al, 2016) and updating the Q-bank database (Bonants et al, 2013), where E. papa sequences appeared under the name E. similaris. Since the scientific name is the only universal way to refer to a species, it is essential to prevent ambiguities that may arise from the simultaneous use of two species names for the same specimens due to misidentification.…”

“…Distance analyses between E. similaris and E. papa DNA barcode sequences obtained for E. similaris specimens were compared with public sequences of E. papa specimens from Portugal (Germain et al, 2013) (Table 2). Pairwise nucleotide sequence divergences were calculated using a Kimura two-parameter (K2P) model of substitution (Kimura, 1980) in MEGA v. 6.0, using the 'pairwise deletion' of gaps option (Tamura et al, 2013).…”

Pest survey card on Epitrix cucumeris, Epitrix papa, Epitrix subcrinita and Epitrix tuberis

“…occurring in Europe and North America (Germain, et al, 2013). These are deemed valuable in identifying all developmental stages of Epitrix spp.…”