author(s)
RD Alibon, JM Gonzales, AE Ordoyo and GG Madjos

abstract
Assessment of ecophenotypic variation in response to microhabitat adaptation is currently one of the prospective approaches to bio-indication. This present study has evaluated conchological variations in the arcid bivalve Anadara maculosa (common cockle) populations in two varying microgeographically–isolated microhabitats (mangrove estuarine and residential intertidal areas) of Margosatubig, Zamboanga del Sur, Mindanao, Philippines. Ecological parameters known to affect the bivalve’s phenotype were obtained in each site such as spatial distribution, edaphic and climatic factors, and resource use. Results of Multi-Analysis of Variance (MANOVA) on the conchological characters (length, width, height, umbo distance, ridge number and total body weight) reveal significant variations (p=1.898e^-7 at α = 0.0001). Further, shape variations based on elliptic Fourier descriptors using SHAPE v.1.3 software tool reveal significant variations (p=0.0268 at α = 0.05). This variation analysis is indicative of high ecological plasticity of this species which may be attributed to ecological condition of its microhabitat.