敌敌畏对多疣狭口蛙不同发育期蝌蚪的急性毒性影响

为了解农药对不同发育期蝌蚪的毒性,以多疣狭口蛙Kaloula verrucosa蝌蚪为对象,采用水生生物急性毒性试验方法,研究杀虫剂敌敌畏(DDVP)对25期、26期、35期和42期蝌蚪的急性毒性影响.结果表明,在水温19.5～22.0℃条件下,敌敌畏对各期蝌蚪96 h LC50分别为1.13、1.43、1.38和0.61 mg/L,各期蝌蚪对敌敌畏的敏感顺序为42期>25期>35期>26期.由此得出敌敌畏对25期、26期和35期蝌蚪属中等毒性,对42期蝌蚪则表现为高毒.因此建议农药施用应尽量避开蝌蚪的变态期进行.蛙类胚胎期(出膜后)随着发育对外界环境的耐受性增强,蝌蚪期随着发育对外界环境的敏感性增强.鉴于42期蝌蚪意外死亡率高的特点,认为不宜采用变态期蝌蚪进行急性毒性试验.

Acute Toxicity Influence of Dichlorvos on Kaloula verrucosa in Different Period Tadpoles

In order to know the toxicity of pesticide to different period tadpoles, we used Kaloula verrucosa tadpoles as test object and with the acute toxicity test method, studied the acute toxicity influence of the insecticide dichlorvos (DDVP) to 25~(th), 26~(th)，35~(th), and 42~(nd) period tadpoles. The results showed that in 19.5～22.0℃ in water, the 96h LC_(50) values were 1.13, 1.43, 1.38 and 0.61 mg/L for the different growth periods, and the order of sensitive is 42~(nd)>25~(th)>35~(th)>26~(th) period. Dichlorvos to the 25~(th), 26~(th) and 35~(th) period tadpoles is of medium toxicity, while it is highly toxic to the 42~(nd) period tadpoles. So we suggested that we should avoid the abnormality period of tadpoles when used the pesticide. We consider that with the growth stage of the frogs embryonic period (after coming out of the membrane), the resistance to the environment is enhanced while with the growth stage, the tadpoles' sensitivities are strengthened. The unexpected mortality of 42~(nd) period tadpoles is so high that take the tadpole in that period to acute toxicity experiment is unsuitable.