茶小绿叶蝉成虫体表纳米网粒体防护层的破坏与修复

Damage and repair of the nano-sized brochosomal protection layer on the surface of the adults of the tea green leafhopper,Empoasca onukii(Hemiptera:Cicadellidae)

【目的】茶小绿叶蝉Empoasca onukii体表覆盖的纳米网粒体颗粒具有防蜜露粘黏、抗杀虫剂渗透等屏障作用。本研究尝试探索造成叶蝉体表网粒体防护层破坏的方法,跟踪分析茶小绿叶蝉成虫网粒体防护层破坏后的分泌节律及修复行为,并观察网粒体涂抹器的微观形态,以期阐明茶小绿叶蝉成虫涂抹修复纳米网粒体防护层的具体特征。【方法】用清水喷雾、喷粉和高湿处理以及用添加不同表面活性剂[0.2%洗洁精、 0.5%吐温80和0.05%有机硅助剂丝润(Silwet 618)]的杀虫剂喷雾(0.05 mg/L联苯菊酯)处理茶小绿叶蝉成虫,用指示剂药斑法及扫描电子显微镜(scanning electron microscope, SEM)观察这些处理对成虫翅面网粒体的破坏效果;以有机硅助剂丝润分别喷雾以及单翅涂抹成虫两种方式进行破坏处理,并以不做任何处理的成虫为对照组,通过可拍照显微镜记录成虫翅面出现网粒体白斑次数,并通过网粒体白斑次数分析不同处理组成虫网粒体分泌节律变化;通过Vegas软件分析茶小绿叶蝉网粒体涂抹动作,利用器官破坏法确定网粒体涂抹器所在部位,并通过SEM观察其微观结构。【结果】清水喷雾、粉尘和高湿环境不会对茶小绿叶蝉成虫体表网粒体防护层造成破坏,加有机硅助剂丝润的杀虫剂喷雾可在成虫翅面产生明显药斑,SEM图片显示网粒体与残留有机硅助剂团聚结块并掉落;有机硅助剂丝润喷雾处理组成虫网粒体的分泌间隔时长为(22.3±1.8) h,比对照组缩短了约8.0 h, 5 d内有机硅助剂丝润喷雾处理组成虫网粒体分泌频次为(8±1)次,比对照组高出约3次;成虫往体表涂抹修饰网粒体时前后足的振动频率可达(16.7±2.4) Hz;器官破坏法处理后足胫节微毛列造成叶蝉无法正常涂抹网粒体,这可能是由涂抹器微毛顶端反向弯曲造成的。【结论】有机硅助剂丝润可破坏茶小绿叶蝉成虫体表网粒体防护层,有机硅助剂处理后茶小绿叶蝉通过缩短网粒体的分泌间隔时长来修复网粒体防护层;前后足振动频率以及胫节微毛末端的正常弯钩是茶小绿叶蝉成虫完成纳米网粒体颗粒涂抹的关键。

【Aim】Brochosomes,which are nano particles covering on the body surface of the adults of the tea green leafhopper,Empoasca onukii,can avoid the stickness of their own sticky exudates and the permeability of insecticide droplets.In this study,we tried to explore the methods to damage the brochsomal protedion layer,to analyze the rhythm of brochosome secretion and the repairing behaviors of E.onukii adults after damage to the brochosomal protection layer,and to observe the micromorphology of the brochosome-anointing organ,so as to clarify the specific characteristics of repairing the nano-sized brochosomal protection layer of E.onukii adults.【Methods】E.onukii adults were treated with water spraying,powder injection and a high-humidity condition,and insecticide spraying(0.05 mg/L bifenthrin)with different surfactants(0.2%detergent,0.5%Tween-80,and 0.05%organosilicon adjuvant Silwet 618).The damage effects of these treatments on the brochosomal integument of adults were observed by the indicator-plaque method and scanning electron microscope(SEM).The adults were sprayed and the single wing was smeared with organosilicon adjuvant(Silwet 618)solution as damaged treatments,with untreated adults as the control.The frequency of white brocosomal spots was recorded by a pohotographic microscopy and the rhythm of brochosome secretion was analyzed by the frequencies of white brochosomal spots.The brochosome-anointing behaviors were analyzed by the Vegas software.The location of the brochosome-anointing organ was verified by the organ-ablated method,and the microstructures were observed by SEM.【Results】The brochosomal protection layer of E.onukii adults was not damaged by the treatments with water spraying,powder injection and a high humidity condition,while obvious plaques on the adult wings were caused by the spraying with insecticide plus organosilicon adjuvant(Silwet 618)solution.The SEM images showed that brochosomes were agglomerated with residual adjuvants and fell off.The interval time of brochosome secretion in the organosilicon adjuvant Silwet-sprayed adults was(22.3±1.8)h,which was about 8.0 h shorter than that in the control.Within 5 d post spraying,the frequency of brochosome secretion in the organosilicon adjuvant Silwet-sprayed adults was(8±1)times,which was about 3 times more than that in the control.The vibration frequeny of the forelegs and hindlegs of adults could reach(16.7±2.4)Hz.After the delicate setae row on the ventral side of hindleg tibia was treated with the organ-ablated method,the adults were unable to anoint the brochosomes normally,which might be due to the reverse bending of the hooked apices of delicate setae.【Conclusion】The organosilicon adjuvant Silwet 618 can damage the brochosomal protection layer on the body surface of E.onukii adults.The adults of E.onukii repair the brochosomal layer by shortening the interval time of brochosome secretion after organosilicon adjuvant treatment.The moving rate of foreleg and hindleg and the normally-hooked apices of the tibia are the key factors to anoint the nano-sized brochosomes in E.onukii adults.