Imidacloprid Affects Pardosa Pseudoannulata On Growth, Reproduction, Function Of Predation And Activity Of Enzymes In Vivo

Imidacloprid is a nicotine-based, systemic, widely used insecticide. The evaluation of the effects of imidacloprid on the spiders, the result is very important for protection of the farmland spider and utilization imidacloprid. In this study, the acute toxicity of imidacloprid on Pardosa pseudoannulata were analysed, and the fecundity, development time of unexposed offspring, predation, and the activities of detoxification enzymes were also conducted. All these results will provide useful theoretical and empirical foundation for later studies. The followings are the main results of this study.1The acute toxicity of imidacloprid on P. pseudoannulata: The acute toxicity of imidacloprid on P. pseudoannulata evaluated by the dipping method under laboratory conditions. The results showed that the mortality rates of P. pseudoannulata differed significantly among different treatments, and rose with increasing concentrations of imidacloprid. The nominal LC50of imidacloprid for P. pseudoannulata was calculated as40.44mg/L.2The effects of imidacloprid on the fecundity and growing development of P. pseudoannulata:The effects of imidacloprid(12.5mg/L,25mg/L,50mg/L,100mg/L and200mg/L)on the fecundity and growing development of P. pseudoannulata evaluated by the dipping method under laboratory conditions. The results showed that the growing development of P. pseudoannulata exposed to imidacloprid (200mg/L) was64.29±1.02days, significantly longer than the control; The females exposed to imidacloprid (200mg/L) produced46.7±1.02eggs less than the control group. With higher doses of imidacloprid, the development time of the spiderlings lengthened.3The effects of imidacloprid on the predation of P. pseudoannulata:In five differences concentrations of imidacloprid (12.5mg/L,25mg/L,50mg/L,100mg/L and200mg/L),functional responses of P. pseudoannulata on Drosophila melanogaster were evaluated under laboratory conditions. The results showed that the high concentrations of imidacloprid (concentration higher than25mg/L) were significantly weaker predation on D. melanogaster than the control group, but a low dose of imidacloprid (12.5mg/L)increased predation ability. These results suggest that imidacloprid in low concentration can stimulate the performance of spiders.4The effects of imidacloprid on the activities of detoxification enzymes of P. pseudoannulata:In five differences concentrations of imidacloprid (12.5mg/L,25mg/L,50mg/L,100mg/L and200mg/L), the effects of imidacloprid on the activities of detoxification enzymes of P. pseudoannulata were evaluated under laboratory conditions. The activity of CarE was highest in the concentration of12.5mg/L. With higher doses of imidacloprid treatment, CarE activity was significantly lower. Treatment with different concentrations of imidacloprid to P. pseudoannulata. the AChE activity was significant different from control group except12.5mg/L. With higher doses of imidacloprid treatment, AChE activity was significantly lower. We found imidacloprid also caused inhibition of MFO activity in P. pseudoannulata. With higher doses of imidacloprid treatment, MFO activity was significantly lower. This was significantly different between control group and treatment group.