Westrich (1989) and Scheuchl (1996), erroneously state that the species is probably oligolectic on Lythrum sp. (Lythraceae).
Information summarised by Celary (2005) states that the species is narrowly oligolectic on Campanula. He lists the following plant species as sources of pollen: Campanula persicifolia, Campanula rotundifolia (Campanulaceae). Convolvulus arvensis (Convolvulaceae) and Lythrum salicaria (Lythraceae) are cited as nectar sources.
Michez (2007) confirms that for the 49 specimens he studied which carried floral visitation data, all were recorded at Campanula (Campanulaceae).
Levchenko (2009) lists the following as a forage source in the Moscow region of Russia: Lavatera thuringiaca (Malvaceae)