Genetic variability of Cheilosia urbana (Diptera, Syrphidae).

Cheilosia urbana (Meigen, 1822) (Diptera, Syrphidae) belongs to the genus Cheilosia which
comprises 445 currently described species worldwide. Despite the lack of morphological
differences, previous research has revealed high intraspecific genetic variability of C. urbana
suggesting the existence of potential hidden or cryptic taxa. In order to provide additional
information on this subject, the 5’ and 3’ ends of the mitochondrial cytochrome c oxidase
subunit I gene (COI) were analyzed. In total, 41 C. urbana specimens were collected from
14 different localities in 7 European countries (Greece, Spain, Serbia, Montenegro, Hungary,
Switzerland, Slovenia) and Turkey. The results have shown high haplotype diversity for both
analyzed regions of the COI gene (Hd = 0,96 for both 3’ and 5’ COI regions). Additionally,
the construction of phylogenetic trees revealed that certain specimens from different
geographically distant localities are clustered together into monophyletic clades with often
moderate to high bootstrap support. Furthermore, in some cases, specimens from the same
localities are placed in multiple independent clades (e.g. specimens from Simplon Dorf,
Switzerland are placed with those from Greece and Slovenia in one monophyletic clade,
with specimens from Hungary and Serbia into a second monophyletic clade, while one of
the specimens from Switzerland forms a separate independent branch). Similar cluster
formation is observed for specimens from other localities as well. These findings indicate
possible presence of cryptic species with overlapping distribution and stress the importance
of the application of molecular markers in the assessment of hoverfly species diversity.