沙葱萤叶甲成虫触角感器超微结构及对沙葱挥发物的触角电位反应

Ultrastructure of antennal sensilla and electroantennographic responses to Allium mongolium volatiles in adult Galeruca daurica(Coleoptera:Chrysomelidae)

【目的】明确沙葱萤叶甲Galeruca daurica成虫触角感器类型及对寄主植物挥发物的电生理反应,为进一步研究沙葱萤叶甲的化学感受机理奠定基础。【方法】使用扫描电子显微镜观察沙葱萤叶甲成虫触角上的感器类型;采用顶空动态吸附收集法采集寄主植物沙葱Allium mongolium的挥发物,利用气质联用仪测定沙葱主要挥发物组分,并利用触角电位技术(electroantennogram,EAG)测定沙葱萤叶甲成虫对这一寄主植物主要挥发物成分的电生理反应。【结果】沙葱萤叶甲成虫触角上分布的感器主要有5种类型,分别是毛形感器(sensilla trichodea,ST)、刺形感器(sensilla chaetica,SC)、锥形感器(sensilla basiconica,SB)、钟形感器(sensilla campaniformia,SCa)和Böhm氏鬃毛(Böhm bristles,BB)。沙葱挥发物主要由32种化合物组成,其中,含硫化合物占总量的49.3%。雌成虫对二烯丙基硫醚、二烯丙基二硫、顺-2-己烯-1-醇、2-己烯醛、苯甲酸甲酯和己醛6种化合物表现出较强的触角电位反应,雄成虫仅对二烯丙基二硫和2-己烯醛表现出较强的触角电位反应,雌成虫对多数气味化合物的触角电位反应均强于雄成虫。当浓度为1 mol/L时,测试的6种化合物(除2-己烯醛外)均能激发沙葱萤叶甲成虫产生最强的触角电位反应。【结论】沙葱释放的6种化合物二烯丙基硫醚、二烯丙基二硫、顺-2-己烯-1-醇、2-己烯醛、苯甲酸甲酯和己醛能引起沙葱萤叶甲成虫强烈的触角电位反应,且除2-己烯醛外,沙葱萤叶甲对各化合物的EAG反应随着浓度的上升而增强。

【Aim】This study aims to clarify the types of antennal sensilla and electrophysiological responses of the adult Galeruca daurica to volatiles of host plants,so as to provide the necessary basis for further investigation on the mechanism of chemoreception in G.daurica.【Methods】The sensilla types on the antennae of G.daurica adults were observed using scanning electron microscopy(SEM).The volatiles were collected from the host plant Allium mongolium by headspace dynamic adsorption collection method,and the main components of volatiles were determined by GC-MS.The electrophysiological responses of G.daurica adults to the main volatile components of this host plant were determined by electroantennogram(EAG).【Results】There are five types of sensilla on the antennae of G.daurica adults,including sensilla trichodea(ST),sensilla chaetica(SC),sensilla basiconica(SB),sensilla campaniformia(SCa)and Böhm bristles(BB).Thirty-two volatile components were identified from A.mongolium.Among them,sulfur compounds accounted for 49.3%.EAG results showed that six compounds including diallyl sulfide,diallyl disulphide,(Z)-2-hexen-1-ol,2-hexenal,methyl benzoate,and hexanal elicited relatively strong eletrophysiological responses in female adults of G.daurica,while only diallyl disulphide and 2-hexenal elicited relatively strong EAG responses in male adults.Moreover,most of the tested compounds elicited stronger EAG responses in female adults than in males.At the concentration of 1 mol/L,the tested six compounds except 2-hexenal could elicit the strongest EAG response in G.daurica adults.【Conclusion】Six compounds of A.mongolium can elicit strong EAG response of G.daurica adults,including diallyl sulfide,diallyl disulphide,(Z)-2-hexen-1-ol,2-hexenal,methyl benzoate,and hexanal.The EAG responses of G.daurica adults to all these compounds except 2-hexenal increase with increasing concentrations.