Evidence of Shell Shape Variation in the Population of Golden Apple Snail (Pomacea canaliculata Lamarck, 1822) in the Second Largest Lake (Mainit) in Mindanao, Philippines

Abstract

Morphometric techniques have been employed in systematic biology studies to quantify and analyze biological shape variation. This study aims to describe the phenotypic variation and sexual dimorphism of the Golden Apple Snail, (Pomacea canaliculata), with notes on physicochemical parameters from Lake Mainit, Surigao del Norte. 180 shells of adult gastropods of uniform size were collected across the three Barangays (San Roque, San Pablo, and Magsaysay). Using Relative Warp Analysis to discriminate the shell shapes. The anatomical landmark points were employed in the Multivariate Analysis of Variance, Principal Component Analysis, and Canonical Variate Analysis. Results demonstrated a significant difference (P < 0.05) in shell shape across the sampling sites and between the sexes. This indicates a distinctive morphological variation and is evidence of sexual dimorphism. Further, the highest variations were found in the female ventral region when compared to male dorsal regions. The observed variability may possible associated with foraging activities, diet, predation, habitat selection, and ecological response. Thus, using this modern tool allows us to identify intraspecific shell shape differences.