Stark John D, Vargas Roger I
Department of Entomology, Ecotoxicology Program-Pyallup Research and Extension Center, Washington State University, 7612 Pioneer Way, Puyallup, WA 98371, USA.
Ecotoxicol Environ Saf. 2003 Nov;56(3):334-8. doi: 10.1016/s0147-6513(02)00074-x.
The toxicity of the natural insecticide spinosad was assessed against Daphnia pulex (Leydig) using a demographic approach. Data were also generated for the commonly used organophosphorus insecticide diazinon as a comparison. Exposure to spinosad led to a concentration-dependent decline in survival, birth rate (b), net reproductive rate (R(0)), and intrinsic rate of increase (r(m)). Population extinction (-r(m)) occurred after exposure to spinosad concentrations >10 microg/L for 8 days. Exposure to increasing diazinon concentrations led to an initial increase in R(0) and r(m) followed by a sharp decline, with extinction occurring after exposure to >2 microg/L after 2 days. Based on concentrations of pesticide that caused population extinction, spinosad was five times less toxic than diazinon. The stable age distribution (after 65 days) of D. pulex changed after exposure to spinosad and diazinon. Increasing concentrations of spinosad resulted in a decrease in the percentages of individuals in the first juvenile and adult stages, increase in the third and fourth juvenile stages, and little or no change in the second juvenile and adolescent stages. Diazinon had a different effect on stable age distribution. Increasing concentrations of diazinon resulted in an increase in percentages of individuals in the first and second juvenile stages, little or no change in the third and fourth juvenile stages and adolescent stage, and a decrease in the adult stage. Although spinosad and diazinon are both neurotoxins, they have different modes of action and populations of D. pulex reacted differently to each pesticide. Results of this study indicate that spinosad is significantly less toxic than diazinon to D. pulex and because it is applied at lower concentrations than diazinon it should be less hazardous to this species.
采用种群统计学方法评估了天然杀虫剂多杀菌素对蚤状溞（莱迪希）的毒性。还生成了常用有机磷杀虫剂二嗪农的数据作为比较。暴露于多杀菌素会导致存活率、出生率（b）、净生殖率（R(0)）和内禀增长率（r(m)）呈浓度依赖性下降。暴露于浓度>10微克/升的多杀菌素8天后，种群灭绝（-r(m)）发生。暴露于不断增加的二嗪农浓度会导致R(0)和r(m)最初增加，随后急剧下降，暴露于>2微克/升2天后发生灭绝。基于导致种群灭绝的农药浓度，多杀菌素的毒性比二嗪农低五倍。暴露于多杀菌素和二嗪农后，蚤状溞的稳定年龄分布（65天后）发生了变化。多杀菌素浓度增加导致第一幼体期和成年期个体百分比下降，第三和第四幼体期个体百分比增加，第二幼体期和青春期个体百分比变化很小或没有变化。二嗪农对稳定年龄分布有不同影响。二嗪农浓度增加导致第一和第二幼体期个体百分比增加，第三和第四幼体期以及青春期个体百分比变化很小或没有变化，成年期个体百分比下降。尽管多杀菌素和二嗪农都是神经毒素，但它们具有不同的作用方式，蚤状溞种群对每种农药的反应也不同。本研究结果表明，多杀菌素对蚤状溞的毒性明显低于二嗪农，并且由于其施用浓度低于二嗪农，对该物种的危害应该较小。
