Fig. 2

Spider behaviour on water surface and tiptoeing (ballooning) tendency. Behavioural categories and their prevalence (a). Overlap areas indicate combined behaviour. Numbers in parentheses indicate the number of individuals that performed each behaviour. Proportion of each behaviour in species where no individual showed tiptoeing (non-tiptoeing species) (b), in non-tiptoeing individuals belonging to species where tiptoeing was observed (c) and in tiptoeing individuals (d). The inter-species comparisons were between tiptoeing and non-tiptoeing species and the inter-individual comparisons were between tiptoeing and non-tiptoeing individuals, taking account of species difference. Asterisks indicate the level of statistical significance of the likelihood ratio test (*: p <0.05, **: p <0.005, ***: p <0.0005). Error bars, s. e. m