Although sibling species were not identified in the present study, we expect that a high degree of genetic divergence within a particular complex is indicative of cryptic diversity. The results confirm this prediction, as high values of genetic divergence were observed in taxa where sibling species are known: Helodon onychodactylus complex (max. 4.91%), Stegopterna mutatacomplex (max. 5.47%), Simulium(Simulium) arcticumcomplex (max. 6.5%), Simulium (Simulium)tuberosumcomplex (max. 5.44%), Simulium (Simulium)venustumcomplex (max. 5.31%). Maximum values of genetic divergence in these species
complexes were well above those observed in S. (N.)silvestre, S. (S.)rostratumand P. travisi s.s. (i.e. 3.36–3.84%).