Predation risk alters shape
Analysis of Daphnia shape using Procrustes ANOVA revealed that shape varied across all factors, including size, instar, clone and predation risk (all p < 0.001). The response to the level of predation risk did not vary by instar (predation x instar interaction; F = 1.39, df = 5, p = 0.13), but it did vary by genotype (predation x genotype interaction; F = 4.92, df = 10, p < 0.001). The phenotypic trajectory analysis showed that this interaction was not based around how much the clones responded to predation cues (path distances were equivalent, all pairwise differences p > 0.05), but around differences in the direction of these changes in multivariate trait space (the angle of the change in shape space) and the shape of these changes (the relative position of the changes in shape space, all pairwise differences p < 0.01) along the six cue concentration gradient (Fig. 3-5). Specifically, the direction of change in clone ‘Cletus’ differed from both clone ‘Chardonnay’ and ‘Carlos’ (both p < 0.05) indicating that the landmarks that changed in ‘Cletus‘ were different than in the other two clones and we can see the evidence for differences in the shape of the trajectories in Fig. 5, where each clone follows a slightly different path along the cue concentration gradient.