Mean (±s.e.) proportion change in line crosses from the pre-stimulus baseline for woodfrog tadpoles exposed to water (black bars), salamander odour (grey bars) or crushed tadpole cues (white bars) in the (a,b) morning or (c,d) evening. As embryos, woodfrogs were conditioned for 7 days with water, salamander odour (sal) or crushed tadpoles paired with salamander odour (TP + sal) in the (a,c) morning or in the (b,d) evening.