As this is a cleptoparasitic species, all flower visits will be for nectar only.
Known nectar sources in Germany include Knautia arvensis (Dipsacaceae); Hieracium pilosella, Anthemis tinctoria (Asteraceae); Potentilla argentea (Rosaceae) (Westrich, 1989).
Celary (1995) lists the following nectar sources in Poland: Veronica chamaedrys (Scrophulariaceae); Salvia pratensis, Thymus serpyllum (Lamiaceae); Knautia arvensis (Dipsacaceae); Anthemis tinctoria, Senecio vernalis, Senecio jacobaea, Taraxacum officinale, Hieracium pilosella (Asteraceae).
Data from Lesvos adds Anthemis arvensis, Crepis commutata (Asteraceae); Sarcopoterium spinosum (Rosaceae).