Distribution and taxonomy of two closely related Nychiodes species in southern Italy (Lepidoptera, Geometridae, Ennominae)

We investigated the distribution and species circumscription of Nychiodes obscurariaVillers (1789) and Nychiodes ragusaria Millière (1884). The morphology of male and female genitalia of Calabrian populations (southern Italy) revealed them to belong to N. ragusaria while specimens from Basilicata, Molise and the rest of Italy turned out to be N. obscuraria. Although the DNA barcodes showed a divergence of 1.55% between typical N. obscuraria and N. ragusaria, 9 out of 28 Calabrian specimens of N. ragusaria shared the N. obscuraria haplotype, and sometimes both haplotypes were found at the same site. Genetic introgression appears as the most probable scenario to explain the observed pattern. A correct identification for the investigated species pair should be based on morphology instead of DNA barcode analysis because of the observed mitonuclear discordance at mountain sites. Further studies are needed to clarify the occurrence of this discordance at high elevations only.