低剂量农药对稻田蜘蛛生态位及控虫效能的影响

通过对稻田蜘蛛优势种和目标害虫空间生态位的研究发现,低剂量浓度的杀虫双其结构式为(CH3)2NCH(CH2S2O3Na)2]农药V(原药)∶V(水)=12∶5 000]能较大地增加稻田蜘蛛的空间生态位宽度及蜘蛛与害虫的比例相似性指数,且蜘蛛空间生态位宽度的增加幅度大于害虫.但随着时间的推移,其空间生态位宽度与害虫的比例相似性指数逐渐减少,直至恢复到未施药的水平.通过系统的研究发现,在合适的低剂量农药作用下,蜘蛛能维护较高的相对活力约1周的时间.通过对蜘蛛控制害虫的生物量测定,发现低剂量农药能显著的增加天敌对害虫的捕食量.

Influences of Low-dose Pesticide on the Spatial Niche and Insect-controlling Efficiency of Paddy Field Spiders

By the research of spatial niche of spiders and objective pests,the result made it clear that the low-dose Shachongshuang pesticide was found to increase the spatial niche breadth of them and similarity indices of inter-taxa of spiders and pest insects,and that spatial niche breadth values of spiders was bigger than that of objective pests.But spatial niche breadth of spiders and similarity indices of inter-taxa of spiders and pest insects gradually decreased,at last returned to normal level.It found that spiders could maintain on time a higher activity for 7 days or so under low-dose Shachongshuang pesticide(pesticide∶H-2O=12∶5 000).The result of biomass of pests under spiders showed that the most suitable low-dose chemical pesticide could remarkablely increase the insect-controlling efficiency of paddy field spiders.