Amiet et al. (2010) suggested that the species may be oligolectic, in that it prefers to forage upon a narrow range of flowering plants, specializing on species of Sempervivum (Crassulaceae), and indeed in Austria it has been recorded collecting pollen predominantly on Sempervivum montanum (Ebmer 2003a, 2003b). In Switzerland, floral records include a preference for Saxifraga aizoides (Saxifragaceae) (Frey-Gessner 1904).
Müller (2018) has reviewed the lectic status and reports that the species is polylectic with strong preference for Sempervivum (Crassulaceae). Müller (2018) lists the following pollen sources in the Alps:
Sempervivum (Crassulaceae); Saxifraga (Saxifragaceae); Helianthemum (Cistaceae); Lamiaceae (Nepetoideae); Potentilla-type (Rosaceae); Asteraceae (Asteroideae); Calluna (Ericaceae); Gentianaceae; Brassicaceae; Caryophyllaceae