Figure 1From: Immune response to sympatric and allopatric parasites in a snail-trematode interactionMean prevalence Microphallus infection (1 s.e.) of the snail host P. antipodarum in relation to parasite source, host source, and dose of parasite: (a) low dose, and (b) high dose. Vertical standard error bars were estimated from the mean squared error in the ANOVA in Table 1.Back to article page