The hidden diet – examination of crop content reveals distinct patterns of pollen host use by Central European bees of the genus Hylaeus (Hymenoptera, Colletidae)

Important pollen hosts of Central European Hylaeus species. (a) Daucus carota (Apiaceae) and Hylaeus cornutus (photo S. Falk). (b) Potentilla recta (Rosaceae) and Hylaeus brevicornis (photo A. Haselböck). (c) Rubus spec. (Rosaceae) and Hylaeus spec. (photo B. Jacobi). (d) Reseda lutea (Resedaceae) and Hylaeus signatus (photo A. Krebs). (e) Melilotus albus (Fabaceae) and Hylaeus spec. (photo N. Vereecken). (f) Centaurea scabiosae (Asteraceae, Carduoideae) and Hylaeus nigritus (photo A. Krebs). (g) Allium sphaerocephalon (Amaryllidaceae) and Hylaeus punctulatissimus (photo A. Müller). (h) Campanula trachelium and Hylaeus spec. (photo A. Krebs).