Changes in Ambient [Ca2+] Impact Reproduction and Development in Lymnaea Stagnalis

The freshwater pond snail, Lymnaea stagnalis, is extremely well studied and a model organism in many scientific disciplines including physiology and ecotoxicology. This species produces egg masses that hatch within an average of 10-14 days of development with a fully developed CaCO₃ shell. A lot is known regarding calcium (Ca²⁺) acquisition in adult mollusks but less is known about the development and Ca²⁺ acquisition of mollusk embryos. Ca²⁺ is a vital element for reproduction, development, and overall biological function. Previous studies have shown that the development of L. stagnalis is impaired by a reduction in ambient Ca²⁺ concentrations, and that adults prioritize Ca²⁺ uptake over other biological functions. In this study I delineate the impacts of Ca²⁺ on the reproduction and development of Lymnaea stagnalis. Impacts were determined through monitoring of the Ca²⁺ acquisition by laid egg masses as well as the provisioning and production of eggs by adults in varying Ca²⁺ environments. Adult L. stagnalis fully provision egg masses with [Ca²⁺] despite low [Ca²⁺] environments while significantly reducing reproductive output. Interestingly, there were no measured impacts on adult Ca²⁺ homeostasis, and adults did not consume more food to supplement their Ca²⁺ needs in low [Ca²⁺] conditions. Lymnaea stagnalis appears to be able to control the calcium content of their egg masses and control their reproductive output to adapt to changes in their environment. Results show that adult snails prioritize the quality of egg masses over quantity in low [Ca²⁺] environments. Limited reproduction in low [Ca²⁺] can have detrimental impacts on L. stagnalis populations as water acidification and freshwater [Ca²⁺] continues to impact aquatic systems.