Fig. 2.

Oil-collecting bee species visiting the flowers of N. linariifolia: (A) the large-sized Tapinotaspis chalybaea sweeping the entire oil-producing area with the oil-collecting brushes on its long middle legs, with the anthers and stigma in contact with the ventral part of the thorax; (B) the small-sized Chalepogenus parvus collecting oil with its forelegs on a sector of the corolla without pollinating; (C) the medium-sized Ch. nigripes collecting oil with its forelegs, with the anthers and stigma in contact with its forehead; (D) the large-sized Centris tricolor seizing the stamens with its mandibles and sweeping a large area of the corolla with the foreleg oil-collectors; similarly to Ch. nigripes with the anthers and stigma in contact with the forehead.