Figure 1.

Effects of water satiation on CRs to water-associated odour after standard training. (a) Two groups were each subjected to a pre-training test and then four-trial (four trials × 1 day) training. On the next day, crickets in one of the two groups were given water at 1 h prior to the post-training test until they stopped drinking (water-satiated group) and those in the other group were not given water (control group). (b) The effect of giving water until satiation on responses to an odour CS after conditioning with sucrose US compared to that after conditioning with water US was evaluated by comparing among three groups. Two of the three groups were each subjected to a pretest and then four-trial training with 0.5 M sucrose reward. On the next day, crickets in one group were given water until satiation at 1 h prior to the post-test and those in another group were subjected to the test without being given water. The last group was subjected to a pretest and then four-trial training with water reward. On the next day, crickets in this group were given water at 1 h prior to the post-test. The time schedules of experiments are shown above the graphs. Peppermint odour was used as CS and vanilla odour was used as the control odour (indicated as p/v). Relative preference for the rewarded odour, measured as the preference index (PI), before training (white box) and that 1 day after training (grey box) are shown as box plots. The results of statistical comparison before and after conditioning (WCX test) and between groups (M–W test) are shown as asterisks (**p < 0.01; ***p < 0.001; n.s. p > 0.05, with the p-values adjusted by Holm's method).