Muller (1996) states that this is a polylectic species, with a strong preference for Cardueae (Asterceae) and Zygophylllaceae. Muller cites Centaurea vallesiaca (Asteraceae) as a pollen source in Switzerland.
Stanisavljević (2000) citing Banaszak & Romasenko (1998) lists Helianthus, Centaurea, Carduus and Cirsium (Asteraceae) as forage sources.
Pollen analysis (Muller, 1996) revealed the following pollen sources: Asteraceae with small amounts of Brassicaceae, Crassulaceae, Rosaceae, Fabaceae, Cistaceae, Apiaceae, Convolvulaceae, Boraginaceae, Dipsacaceae and Campanulaceae