Figure 2.

The learning curves (mean choice accuracy ± SD) for the males (black squares and line, N = 30) and workers, with the latter trained either using a 2 h food deprivation period between foraging bouts (dark grey circles and line, N = 11) or allowing for continuous foraging between colony and feeders (light grey circles and line, N = 40) over 50 visits for each of four serially presented colour pairs. (a) Training sequence A started with yellow rewarding feeders (CS⁺) and blue nonrewarding (CS⁻) followed by green⁺/yellow⁻, purple⁺/green⁻ and blue⁺/purple⁻. (b) Sequence B consisted of purple⁺ and blue⁻ followed by green⁺/purple⁻, yellow⁺/green⁻ and blue⁺/yellow⁻. CD denotes the colour distance in the hexagonal bee colour space between the feeder colours in the presented colour pair ranging from difficult to discriminate (<0.1) to highly discriminable (>0.2).