Molecular tools for resolving Merodon ruficornis group (Diptera, Syrphidae) taxonomy

Considering the threat of pollinator decline to seriously affect ecosystem function and food security, the conservation of pollinating insects has become of utmost importance, entailing the accurate taxa identification in order to establish a long-term monitoring strategy. In addition to pollination service, hoverflies (Diptera: Syrphidae) also have a role as habitat bioindicators, as well as in organic matter recycling and protection of cultivated plants from pests. Representing one of the most species-rich hoverfly genera, Merodon Meigen, 1803 holds numerous taxonomic challenges, especially within the monophyletic Merodon ruficornis species group, which is characterized by incongruence between morphological and molecular data. In the present study, we successfully resolved the taxonomy of the M. ruficornis group using a combination of four genetic markers (3 ' and 5 ' ends of the COI gene, 28S and ITS2) and demonstrate their potential as molecular tools for resolving taxonomic questions within the Merodon genus. We proved the utility of indels as valuable molecular signals for the taxa delimitation within M. ruficornis group by performing two different indels schemes-(1) excluding indels from analysis as missing data; and (2) coding indels as presence/absence character matrix. In addition to the found congruence with morphologically defined species, our results revealed intraspecific differentiation between Anatolian and Balkan populations within three species-M. loewi, M. trebevicensis and M. armipes. According to the divergence time estimates, lineage diversification within the M. ruficornis group probably took place during Pleistocene climatic changes as a consequence of the species' range alterations.

Automated summary

Considering the threat of pollinator decline to seriously affect ecosystem function and food security, the conservation of pollinating insects has become of utmost importance. This study successfully resolved the taxonomy of the Merodon ruficornis group using genetic markers and demonstrated their potential as molecular tools for resolving taxonomic questions within the Merodon genus.