Banaszak & Romasenko (1989), copied by Stanisavljević (2000), and Ivanov et al. (2005) state that the species is oligolectic on various Asteraceae, and visits Centaurea, Carduus and Anthemis.
Composition of scopal pollen contents were studied by Zander (1935). He showed that in a sample of 45 specimens of M. pilicrus, the pollen loads were all Asteraceae, Centaurea jacea type 98.5%, Serratula type 0.8% & Jurinea type 0.7%.
Females of the European leaf-cutter bee Megachile (Megachile) pilicrus Morawitz possess a conspicuous brush of stiff, yellowish-red bristles on the ventral side of the trochanter and femur of their hind legs. Observation of pollen-harvesting females in the field and microscope analysis of scopal pollen contents revealed that the hind leg brush is a specialized device for combing pollen from the inflorescences of thistles and knapweeds (Cardueae, Asteraceae), the exclusive pollen plants of M. pilicrus.