Table 2.

Intensity contrast (C) between the disc and the background. Italic numbers indicate the stimuli selected by the trained butterflies.

	control test		test 1/orange		test 2/orange		test 3/orange		test 1/purple		test 2/ purple		test 3/ purple
experiment 1 (R1-trained)
disc	R1	R2	R1	O2	O2	O4	O2	O2	R1	P1	P1	P3	P2	P2
back	Gr2	Gr2	Gr2	Gr2	Gr2	Gr2	Gr1	Gr3	Gr2	Gr2	Gr2	Gr2	Gr1	Gr3
C	0.24	−0.15	0.24	0.09	0.09	−0.32	−0.32	0.30	0.24	0.23	0.23	−0.14	−0.41	0.21
experiment 2 (R2-trained)
disc	R1	R2	R2	O4	O1	O3	O2	O2	R2	P3	P1	P3	P2	P2
back	Gr2	Gr2	Gr2	Gr2	Gr2	Gr2	Gr1	Gr3	Gr2	Gr2	Gr2	Gr2	Gr1	Gr3
C	0.24	−0.15	−0.15	−0.32	0.09	−0.17	−0.32	0.30	0.24	−0.14	0.23	−0.14	−0.41	0.21