A New Multi-cell Exposure System for Continuous Tracking of Daphnia Behavior for Toxicity Assessments

For several years, video tracking systems have been developed to analyze alterations in the swimming behavior
of daphnia to provide early signals of chemical stress. However, these systems have limited testing abilities that do not
allow for a systematic analysis of the robustness of behavioral endpoints. With recent advances in behavior tracking
technology, we were able to develop a new behavioral analysis multi-cell exposure system named “Multi-DaphTrack”
with a high-throughput testing capacity for assessing the behavioral response of Daphnia magna. The insecticide
esfenvalerate was chosen as chemical model and tested on daphnid neonates at several concentrations for 48 h to
(i) evaluate the performance of this new system and (ii) compare the sensitivity of our new multi-cell system with the
standard immobilization assay and the Bbe®
Daphnia Toximeter. Overall, the results demonstrated that our new “MultiDaphTrack” system can detect significant behavioral effects of esfenvalerate at concentrations as low as 0.14 µg/L from
a minimum of 1 h of exposure. Similar rapid behavioral effect trends were observed with the Bbe®
Daphnia Toximeter.
The behavior proved to be more sensitive than the standard immobilization endpoint. Significant behavioral changes
were observed at the esfenvalerate concentrations that occur in contaminated rivers from agricultural areas in Europe
and North America.