Strongly oligolectic on Campanula (Campanulaceae).
Pollen sources include Campanula trachelium, Campanula patula, Campanula rapunculoides, Campanula rotundifolia and Campanula spicata (Campanulaceae)(Westrich, 1989).
Kemp et al (2014), citing others, states that the species is oligolectic, in that it prefers to forage mainly upon Campanula (Campanulaceae) but it is also found on Geranium pratense (Geraniaceae), Veronica spicata, (Plantaginaceae) and Anthericum ramosum (Asparagaceae).