Müller (2018) states that the species is probably mesolectic on Fabaceae and Ericaceae with strong preference for Loteae (Fabaceae). The species has been reported to have a strong preference for Fabaceae (e.g. Lotus, Hippocrepis); additional pollen sources include Ericaceae (Amiet et al., 2004; A. Müller, unpublished, based 10 pollen samples from 4 different localities and on field observations)
Müller (2018) lists the following pollen sources in the Alps; Lotus, Hippocrepis, Trifolium (Fabaceae); Rhododendron (Ericaceae).