Fig. 2

Group and single emergence test in parental (F0) and F1 adults. A Single emergence time plotted against group emergence ranks of the F0 parental fish during an emergence test. Data were collected from 5 batches of 10 adult zebrafish (N = 50, individuals not emerging within 10 min were omitted from analysis) obtained during a group emergence test (rank) and subsequent single emergence test (time), with a significant correlation between emergence rank in the group test and time in the single test (Spearman rank test, N = after (before outlier elimination); simple linear regression: y = 86.18x − 135.3, r² = 0.14). B Emergence time obtained during a single emergence test of the F1 adults plotted against emergence rank of F0 parental fish during an (N = 100, individuals not emerging within 10 min were omitted from analysis) in the F0 group emergence test (rank) and F1 single emergence test (time), with a significant correlation between rank and time in the single test (Spearman rank test, N = after (before outlier elimination); simple linear regression: y = 22.73x + 60.69, r² = 0.12). These results establish risk taking as a consistent and heritable behavioural trait