Abstract—The shell morphology of O. quadrasi ishypothesized to be driven through coevolution between S.japonicum infectivity capacities with O. quadrasi. Thishypothesis predicts that measures of geometricmorphometricvariations of snail populations parallel variedschistosome infections thus was evaluated in two provincesof Mindanao, Philippines where there were reportedinfections. Relative Warp Analysis was used in theinvestigation to determine shell shape divergence. Forstatistical analysis, Discriminant analysis and Kruskal-Wallis test were performed. The results showed thatparasitism in O. quadrasi had significant effects on somemorphometric dimensions of the snail- apertural and apicalsculptures based on the shell shapes. These phenotypicvariations accounted for more than 40% of the variance inshell morphology relative to mean shape. Even at lowinfection levels, 4.05% of the local populations beinginfected, the effects were even detectable. Analysis ofgeometric morphometrics of the two populations (cercariaeinfectedand uninfected shells) of O. quadrasi based on shellcharacters generally has demonstrated dimorphic featuresin shell shapes.

Index Terms—Geometric morphometric analysis; relativewarps; phenotypic variation; parasitism; O. quadrasi; S.japonicum .  

Cite: Edgar Gary Vasallo, Mark Anthony J. Torres, and Cesar G. Demayo, "Relative Warp Analysis of Parasite–Induced Plasticity in the Shell Shape of the O. Quadrasi", Journal of Medical and Bioengineering, vol. 2, no. 2, pp.120-125, 2013. doi: 10.12720/jomb.2.2.120-125