Polylectic with strong preference for Campanulaceae. It is recorded from Campanula sp., Phyteuma orbiculare (Campanulaceae), Hieracium , Solidago virgaurea, (Asteraceae), Acinos and Thymus (Lamiaceae). (Ebmer, 1984).
In addition to Campanulaceae, Müller (2018) adds: Asteraceae (Cichorioideae); Euphrasia-type (Orobanchaceae); Helianthemum (Cistaceae); Lamiaceae (Nepetoideae); Caryophyllaceae; Linum (Linaceae). Field observations showed that among the Campanulaceae flowers, both Campanula and Phyteuma are exploited for pollen. These results support Friese (1898) and Westrich (1989).
Bossert (2014) reports foraging at Leontodon hispidus (Asteraceae) and Phyteuma sp. (Campanulaceae) in the Austrian Tyrol