Abstract: OBJECTIVE: To explore effect of the chlorpyrifos herbicide (CPF) on growth of Drosophila melanogaster (D. melanogaster). METHODS: Analyzed the median lethal dose (LC₅₀) using Probit after D. melanogaster were treated with 0.5,1.0,1.5,2.0,2.5,3.0 and 4.0 mg/L of CPF for 96 h. According to LC₅₀,weight of D. melanogaster was evaluated after being exposed to 0.04,0.08,0.16 and 0.32 mg/L CPF concentration. The experimental data were analyzed by ANOVA test. RESULTS: The toxicity of CPF to female D. melanogaster (LC₅₀ is 0.447 mg/L) was greater than that for male (LC₅₀ is 0.858 mg/L). There was no statistical significance of the weight changes in female D. melanogaster with different concentrations of CPF at different treatment times (P>0.05). With 0.04~0.32 mg/L CPF,male D. melanogaster had reduction of 0.01 mg on average per day which was significantly different compared with the control group (P<0.05 or P<0.01),and showed clear time-dependent effects. In addition,their weights decreased significantly (ranging between 0.04-0.08 mg) with the treatment of 0.04 mg/L (1/20 of LC₅₀) CPF which showed that male D. melanogaster was extremely sensitive to the toxicity at the low concentration. The weight of male D. melanogaster increased by 0.02 mg at 0.16 mg/L CPF and was significantly different at 72 h and 96 h among each experiment group (P<0.05). And showed clear does-dependent effect. CONCLUSION: CPF had significant impact on the growth of male D. melanogaster as reflected by their weight changes.

Key words: chlorpyrifos, Drosophila melanogaster, median lethal dose, weight, growth, chlorpyrifos, Drosophila melanogaster, median lethal dose, weight, growth