红棕象甲幼虫对吡虫啉敏感性测定及中毒行为学反应

Sensitivity test and behavioral response of Rhynchophorus ferrugineus larvae to imidacloprid

[目的]本文旨在明确红棕象甲幼虫对吡虫啉的敏感性及其中毒后的行为学反应。[方法]采用经口注射法,研究了吡虫啉处理对红棕象甲高龄幼虫的致死中剂量和致死中时间,并分析了经药剂处理后红棕象甲的形态学变化。[结果](1)在供试剂量下,吡虫啉对红棕象甲幼虫的致死中时间(LT_(50))无显著差异,随供试时间延长,致死中剂量(LD_(50))呈现降低趋势,其中在处理后96 h的LD_(50)为每头0.43μg。(2)在每头25μg剂量吡虫啉处理后10~11 min,红棕象甲幼虫丧失活动能力,而在每头62.5~500μg剂量处理中,试虫丧失活动能力的时长介于1~30 min。(3)吡虫啉处理后红棕象甲幼虫的毒理学症状随处理时间延长依次主要表现为:虫体蜷缩、皱缩、抖动、口器持续大张、体壁松软、体壁僵硬、平衡感缺失后恢复等,其中抖动、口器持续大张、体壁僵硬等现象随时间的延长会反复交替出现。除口器持续大张状态外,其余各状态的出现频率的最高值和最低值均在处理后48 h出现。(4)高剂量下个别试虫会出现内容物崩出的现象,且高剂量会更快的完成各毒理学症状的表现。(5)在经过重新喂食后,部分中毒反应出现缓解,其中以口器持续大张状态在喂食后24 h缓解最为明显。[结论]吡虫啉对红棕象甲的LT_(50)与供试剂量大小无明显相关性。经吡虫啉处理后,红棕象甲幼虫出现明显的中毒反应,同时在经过重新饲喂取食后,部分症状会有所缓解。

[Objective]The current study aimed to clarify the susceptibility of R.ferrugineus larvae to imidacloprid and its behav⁃ioral responses to poisoning.[Method]The oral injection method was used to study the lethal medium dosage(LD_(50))and le⁃thal medium time(LT_(50))of imidacloprid treatment on mature R.ferrugineus larvae,and the morphological changes of the lar⁃vae were analyzed.[Results](1)Under the test dose,there was no significant difference in the lethal median time(LT_(50))of imidacloprid of R.ferrugineus larvae,and the lethal median dose(LD_(50))showed a decreasing trend with the extension of the test time,and the LD_(50) after 96 h of treatment was 0.43μg per pest.(2)After treatment with 25μg per pest imidacloprid,the R.ferrugineus larvae lost their activity ability in 10-11 minutes,and the in the dose range of 62.5~500μg per pest,the time for the larvae to lose their activity ability ranged from 1 to 30 minutes.(3)The toxicological symptoms of R.ferrugineus larvae after treatment with imidacloprid mainly included body curling,wrinkling,shaking,continuous gaping of the mouthparts,soft⁃ening of the body wall,stiffening of the body wall,and loss of balance and recovery,among which shaking,continuous gaping of the mouthparts,and stiffening of the body wall would appear alternately with the extension of time.The highest and lowest frequency of the occurrence of all symptoms appeared 48 hours after treatment except the state of continuous gaping of mouth⁃part.(4)In high doses,some larvae showed the phenomenon of content collapse,and high doses would complete the expres⁃sion of various toxicological symptoms more quickly.(5)After re-feeding,some poisoning reactions were relieved,and the continuous gaping of the mouthparts was most significantly relieved 24 hours after feeding.[Conclusion]There was no signifi⁃cant correlation between the LT_(50) of imidacloprid and the test dose of imidacloprid on R.ferrugineus.After imidacloprid treat⁃ment,the larvae of R.ferrugineus showed obvious poisoning reactions,and some symptoms were relieved after re-feeding.