Figure 2: Artificial flowers were made of 1.5 mL centrifuge tubes inserted into the centres of blue plastic discs, 7 cm in diameter. The centrifuge tube was capped so that the bees could not obtain the contained syrup from the surface of the plastic disc. Instead, a small hole (0.5 cm in diameters) had been drilled into one side of each centrifuge tube just below the lip.