Fig. 5. (A,B) Mean (± S.E.M.) colour contrasts of different body parts of typical Nephila pilipes viewed by achromatic and chromatic vision. Broken lines indicate the threshold for colour-contrast detection estimated for honeybees. (C,D) Schematic drawings mimicking the (C) dorsum and (D) ventrum patterns perceived by bees using chromatic vision. Body parts whose colour contrasts were smaller than the discrimination threshold were given the same colour as the background, which was artificially designated as black. Those with significantly higher values were assigned different degrees of grey according to their contrast values. Numbers correspond to areas shown in Fig. 1.