Fig. 5
Right-biased approaches (NOA) in Tinaja cavefish were reduced after fasting. A, B Histograms and density plots showing the L–R NOA ratio (A) and L–R DIR ratio (B) before and after fasting in the indicated populations. In A, more Tinaja cavefish individuals showed L–R balanced approaches (0.33–0.67) after fasting; Pachón cavefish maintained L–R balanced approaches (0.33–0.67) before and after fasting, whereas surface fish showed a slight right bias. L–R NOA ratio = \(\frac{\mathrm{NOA}(\mathrm{right})}{\mathrm{NOA}(\mathrm{right})+\mathrm{NOA}(\mathrm{left})}\). In B, the trends for DIR were similar to those in (A). L–R DIR ratio = \(\frac{\mathrm{DIR}(\mathrm{right})}{\mathrm{DIR}(\mathrm{right})+\mathrm{DIR}(\mathrm{left})}\). C, D Pirate plots showing L–R bias index for NOA (C) and DIR (D). In C, right bias index = \(\frac{\mathrm{max}\{\mathrm{NOA}\left(\mathrm{right}\right),\mathrm{ NOA}\left(\mathrm{left}\right)\}}{\mathrm{NOA}\left(\mathrm{right}\right)+\mathrm{NOA}(\mathrm{left})}\). Tinaja cavefish showed a significantly reduced bias index for NOA after fasting, indicating balanced L–R approaches, whereas the other populations showed no detectable changes. In D, L–R bias index = \(\frac{\mathrm{max}\{\mathrm{DIR}\left(\mathrm{right}\right),\mathrm{ DIR}\left(\mathrm{left}\right)\}}{\mathrm{DIR}\left(\mathrm{right}\right)+\mathrm{DIR}(\mathrm{left})}\). None of the populations showed detectable changes in the bias index after fasting, although Tinaja cavefish showed a nonsignificant trend for reduced bias after fasting. All statistical scores are available in Additional file 1: Table S7. **P < 0.01