Relative Warp Analysis of Parasite–Induced Plasticity in the Shell Shape of the O. Quadrasi

The shell morphology of O. quadrasi is hypothesized to be driven through coevolution between S. japonicum infectivity capacities with O. quadrasi. This hypothesis predicts that measures of geometricmorphometric variations of snail populations parallel varied schistosome infections thus was evaluated in two provinces of Mindanao, Philippines where there were reported infections. Relative Warp Analysis was used in the investigation to determine shell shape divergence. For statistical analysis, Discriminant analysis and KruskalWallis test were performed. The results showed that parasitism in O. quadrasi had significant effects on some morphometric dimensions of the snailapertural and apical sculptures based on the shell shapes. These phenotypic variations accounted for more than 40% of the variance in shell morphology relative to mean shape. Even at low infection levels, 4.05% of the local populations being infected, the effects were even detectable. Analysis of geometric morphometrics of the two populations (cercariaeinfected and uninfected shells) of O. quadrasi based on shell characters generally has demonstrated dimorphic features