The Mediterranean is endowed with a great species diversity, often affiliated with evolutionary processes, landscape discontinuities, Quaternary climatic oscillations, and human presence. Here, we discuss the potential of a methodological framework to explore species genetic structure across landscape in insect groups. We have applied the suggested biogeographic framework, and explored spatial patterns of genetic diversity of nine species of the hoverfly genus Eumerus in the Mediterranean region (Chroni et al. 2019). More specifically, we assessed intraspecific genetic differentiation, tested for a spatially-explicit Bayesian clustering, and evaluated the inferred results based on landscape discontinuities and presence of isolation-by-distance. Overall, the spatial genetic structure analyses inferred (i) two genetic clusters ascribed to allopatric and peripatric processes, as well as to landscape discontinuities (4 species); and (ii) one genetic cluster pointing into the hypothesis of consisting of relict taxa (5 species). We have also identified genetically-diverging regions in the Mediterranean, and discussed the potential driving forces that gave rise to these spatial genetic patterns.

Financial support was provided by the Serbian Ministry of Education, Science and Technological Development, Republic of Serbia, Grant No. 43002 and Grant No. 173002, and European Union (European Social Fund – ESF) and Greek national funds through the Operational Program 'Education and Lifelong Learning' of the National Strategic Reference Framework (NSRF) – Research Funding Program THALES: POL-AEGIS Project, grant MIS 376737. We also acknowledge the program ' rants ΙΚΥ' of the State Scholarships Foundation of Greece, within the framework of the Operational Program 'Education and Lifelong Learning' of the European Social Fund (ESF) NSRF 2007–2013 (contract WP2-SHORT TERMS-19348) for partial financial support of the PhD thesis of Dr Antonia Chroni.