A comprehensive system for detection of behavioral change of D. magna exposed to various chemicals

The purpose of the present study was to develop a sensitive and comprehensive method, based on D. magna swimming behavior, for toxicity assessment of environmental chemicals. Firstly, D. magna swimming in several chambers with different diameters were compared to determine the most suitable container, and then baseline behaviors during light/dark periods as well as reactions to light/dark switching and vibration stimulation were determined. Secondly, after exposure to sub-lethal concentrations of the selected 42 typical chemicals, which were classified into heavy metals, pesticides, fungicides and flame retardants, the alterations in the swimming parameters were evaluated. Our results indicated the 48-well plate was the most suitable chamber for behavioral monitoring of D. magna, and specific responsive patterns of D. magna neonates to light/dark switching and vibration stimulation were observed. The results of the behavioral assays of chemicals suggested that D. magna was the most sensitive to methylmercury-chloride and then to abamectin and chlorpyrifos. The three chemicals at several to dozens of ng/L significantly changed swimming behaviors of D. magna. Furthermore, the alteration in the behavioral parameters (average swimming speed, etc.) induced by the selected chemicals could be ascribed to various modes of actions, confirming the reliability and practicability of the monitoring method.