As this is a cleptoparasitic species, all flower visits will be for nectar only.
On mainland Europe, it visits Potentilla erecta (Rosaceae); Jasione montana (Campanulaceae); Erigeron annuus and Hieracium pilosella (Asteraceae) (Westrich, 1989).
Celary (1995) lists the following nectar sources: Potentilla erecta (Rosaceae); Knautia arvensis (Dipsacaceae); Jasione montana (Campanulaceae); Erigeron annuus, Senecio vernalis, Hieracium pilosella (Asteraceae)
Peeters, Raemakers & Smit (1999) additionally cite Cirsium arvense (Asteraceae). Van der Vecht (1930) states that yellow-flowered Asteraceae are nectar sources.