Crayfish activity, defined as the number of transitions between the two sides of the walking arena, of ablated and intact crayfish in the tested types of dual-choice chambers (50–78% RH and 60–75% RH gradients) and in the control (100–100% RH). For controls, no significant differences were recorded between behaviour of ablated and intact crayfish so they were pooled together. Data with different letters are significantly different at P < 0.05 (one-way ANOVA, unequal N HSD Tukey test).