Abstract—Parasitism often influences the phenotype of gastropods. Many of the resulting changes are due to changes in resource allocation that come with infection. This investigation quantifies some aspects of the parasite-host relationship between cercariae and its intermediate host Bithynia sp. Noticeable differences in the shell shape of parasitized and uninfected Bithynia sp. snails were investigated using. Relative Warp Analysis, Discriminant analysis, and Kruskal-Wallis to determine shell shape divergence of the two populations. These shape divergence accounted for more than 35% of the variance in shell morphology relative to mean shape. Apparently, it may be that broader body whorl, wider aperture, conic to globose shape and bigger snails are more likely to become infected with Bithynia sp., or that narrowly conic, reduced aperture, small-sized relative to the shell shape are more resistant to parasite infections. Hence, the methodology using landmark-based geometric morphometric methods proved to be more profound for the characterization of Bithynia sp. snails even at a subtle degree.

Index Terms—Geometric morphometric analysis, relative warps, phenotypic variation, parasitism, Bithynia

Cite: Edgar Gary R. Vasallo Jr., Jessie M. Gorospe, Mark Anthony J. Torres, Ruben F. Amparado Jr., and Cesar G. Demayo, "Relative Warp Analysis of Parasite–Induced Plasticity in the Shell Shape of Bithynia sp. (Bithyniidae)," Journal of Medical and Bioengineering, Vol. 4, No. 2, pp. 159-164, April 2015. Doi: 10.12720/jomb.4.2.159-164