Marsupial development in the mysid Neomysis integer (Crustacea: Mysidacea) to evaluate the effects of endocrine-disrupting chemicals.

Embryonic development is a crucial time window within an organism's life history. Relatively few studies have focused on understanding the potential effects of endocrine disruptors on embryogenesis in invertebrates. Mysids (Crustacea: Mysidacea) have been used extensively in regulatory toxicity testing and they are the only invertebrate model currently included in the U.S. EPA's Endocrine Disruptor Screening and Testing Program. We developed a method for studying mysid embryonic development in multiwell plates until the release of free-swimming juveniles. This method was used to evaluate the potential effects of the insecticide methoprene, a juvenile hormone analog, on mysid embryogenesis. Embryos were exposed to nominal concentrations 0.01, 1, and 100 microg methoprene/L. Average percentage survival, hatching success, total development time and duration of each developmental stage were analyzed. Embryos exposed to 1 and 100 microg methoprene/L had a significantly lower hatching success and lower survival rates. Our study indicates that in vitro embryogenesis can be used as a valuable tool to study the impact of endocrine disruptors in mysids.