Behavioral Bioassay of Brachionus calyciflorus(rotifer) for Toxic Effect Assessment of Dimethoate

Toxic stress of dimethoate on freshwater rotifer Brachionus calyciflorus was evaluated,using swimming behaviors alteration as sub-lethal endpoint.Alteration of swimming behaviors was examined firstly when the rotifer was exposed under 5 dimethoate concentrations after 6h.The imbalance of swimming direction and inhibition on swimming speed of toxic stress was observed clearly.Alterations of swimming behavior under toxic stress were analyzed and classified into 3 aspects such as swimming direction change,swimming angle change and swimming speed change using principal component analysis.Toxicity test results indicated that the disruption of dimethoate on swimming behavior was high concentration dependent,which is the first study about the mode of dimethoate on different aspects of swimming behavior of rotifer.