Patterns of Depression among Elderly Asian Immigrants to the United States Over the Past DecadeThe influence of calcium on the phenotypic plasticity of Campeloma decisum.

Abstract

Changes in an organisms development or morphology due to external biological and physical cues may be described as phenotypic plasticity. We hypothesized that snails, Campeloma decisum, would exhibit phenotypic plasticity in response to environmental fluctuations in calcium carbonate levels. C. decisum were studied in three lakes of increasing water hardness to determine if shell morphology, rate of growth, and thickness was dependent upon available calcium. No relationships were found between calcium concentrations and any of the measured phenotypic traits. Significant differences between lakes were found in regards to total number of bands, rate of shell growth, and shell thickness between the lakes. Snails inhabiting the lake of mid-range calcium carbonate concentration had significant phenotypic differences from the snails collected in the other two lakes. We reject our hypothesis and discuss other factors which may influence the phenotypes of C. decisum. We propose further research that isolates CaCO3 levels in a controlled environment and on the importance of predation and how it impacts snails' phenotypic plasticity.