As this is a cleptoparasitic species, all flower visits will be for nectar only.
Westrich (1989) lists the following plant species as nectar sources: Salix (Salicaceae); Potentilla verna (Rosaceae); Tussilago farfara, Taraxacum officinale (Asteraceae).
Celary (1995; 2007) lists the following nectar sources: Salix sp. (Salicaceae); Euphorbia cyparissias (Euphorbiaceae); Potentilla verna (Rosaceae); Tussilago farfara, Taraxacum officinale (Asteraceae).
Smit (2004) lists Salix (Salicaceae); Taraxacum officinale, Tussilago farfara (Asteraceae) and Stellaria media (Caryophyllaceae) as nectar sources.