Unlike the Knapweed Fritillary (Melitaea phoebe), the Eastern Knapweed Fritillary is single brooded flying in the spring, overlapping with the first brood of Knapweed Fritillary. It occurs in the hotter regions of southen Bulgaria and here both species may fly together.

The two species are very similar, especially on the topside. However thay can usually be readily separated on underside hindwing characters. Key underside ID features are shown in the accompanying captioned pictures above.