Figure 2.

Graphical illustration of how infection status might generate intraspecific variation in behavioural syndromes, if parasites selectively alter behaviour. (a) A ‘behavioural reaction norm’ plot (Dingemanse et al. 2010b) with two environmental conditions (N, no parasites, and P, with parasites) on the x-axis and values of a behavioural trait on the y-axis, where each individual is represented by two points connected by a line. The parallel lines indicate that this behaviour is unaffected by parasite infection. (b) the reaction norm plot for a second behaviour, where behavioural phenotypes of individuals differ under condition ‘N’ but are all the same in condition ‘P’ (i.e. all show high values when parasitized). (c) The expected correlation between the two behaviours (1 versus 2), with the two ellipses depicting the predicted phenotypic correlations for the parasitized (shaded) and non-parasitized (open) states.