Molecular delimitation of Empoascini (Hemiptera: Cicadellidae) from Argentinean crops and redescription of the female of Matsumurasca curveola

Abstract

Historically, Empoasca (Walsh, 1862) (Typhlocybinae: Empoascini) was a taxonomic repository for species poorly defined by external characters, mostly small and pale green insects. Species of this genus are agriculturally important pests, affecting a wide range of crops worldwide. A recent study divided Empoasca into 17 genera, five recorded from the Neotropical Region. Given the complexity of the group, the need to dissect male genitalia, and the scarcity female descriptions, the aim of the present work was to delimit specimens of the tribe Empoascini assigned to Empoasca (sensu lato) using molecular methods as a complement to traditional morphological techniques. Leafhoppers were collected from aromatic and horticultural crops in Huerta La Anunciación (Abasto, Buenos Aires), using an entomological net and preserved in absolute ethanol at -20°C. Genomic DNA was extracted from abdomens of 100 specimens using the DNeasy Blood & Tissue kit (QIAGEN). The COI barcode region was amplified by PCR and sent for sequencing at Macrogen (South Korea). Obtained sequences were edited and aligned with identified COI sequences of empoascines and an alebrine and high similarity sequences obtained by BLAST from GenBank with Geneious Prime. The final alignment included 119 sequences and 666 bp, which was analyzed with maximum likelihood in IQ-TREE. Results point to four distinct and unrelated species groups, which had a maximum of 0.8% of intraspecific and a minimum of 11.11% interspecific K2P divergences. For three species, females were associated to male specimens and their female genitalia were studied. So far, only Matsumurasca curveola (Oman, 1936) was confidently morphologically identified, the others are still pending morphological identification. Based on these results, the female genitalia of M. curveola was redescribed. This study provides an integrative framework to clarify Empoascini taxonomy and represents a first approximation toward evaluating the potential of the barcoding approach for species delimitation in Argentinian agroecosystems.