引起小菜蛾盘绒茧蜂雌雄差异反应的气味筛选及行为学检测

Sex-biased attraction of Cotesia vestalis by herbivore-induced plant volatiles

小菜蛾盘绒茧蜂Cotesia vestalis是小菜蛾Plutella xylostella幼虫期重要的单性内寄生蜂,在小菜蛾的生物防治上具有广阔的应用前景。寄主植物受到小菜蛾为害后释放的挥发物的种类和释放量会变化,这在小菜蛾盘绒茧蜂搜寻小菜蛾过程中也起到了非常重要的作用。然而,这些寄主植物挥发物对小菜蛾盘绒茧蜂的吸引作用是否存在雌雄差异并不明确。本研究选取了32种十字花科蔬菜受小菜蛾为害后发生变化的气味以及小菜蛾幼虫粪便气味和小菜蛾的性信息素,通过EAG测定了小菜蛾盘绒茧蜂对各种气味物质不同浓度(100、10、1μg/μL)的反应。结果显示,小菜蛾盘绒茧蜂对(E)-4,8-二甲基-1,3,7-壬三烯(DMNT)、苯乙腈、(R)-(+)-柠檬烯、正庚醛4种气味分别在100、100、1μg/μL和1μg/μL的浓度下存在显著雌雄差异。进一步通过"Y"形嗅觉仪对这4种气味进行行为学检验,其中DMNT、(R)-(+)-柠檬烯和正庚醛分别在浓度为10、10μg/μL和0.1μg/μL时可以引起显著的雌雄行为差异。

Cotesia vestalis(Hymenoptera:Braconidae)is an important parasitoid wasp for the larvae of Plutella xylostella,and represents an effective natural enemy for biological control.Damage induced by herbivores alter the profile of plant volatiles that can attract the parasitoid wasp.However,so far it was unclear whether males and females are equally attracted by these odorants.In this study,32 herbivore-induced plant volatiles,3 sex pheromone of P.xylostella and 2 larval frass volatiles in different concentrations were used to record electroantennograms(EAG)and observe behavior from both sexes of C.vestalis.Different responses were observed between sexes with(E)-4,8-dimethyl-1,3,7-nonatriene(DMNT),benzyl cyanide,(R)-(+)-limonene and n-heptanal,used at the concentrations of 100μg/μL,100μg/μL,1μg/μL and 1μg/μL,respectively.Y-tube behavior tests performed with these four odorants revealed significant difference between males and females for DMNT,(R)-(+)-limonene and n-heptanal,at the concentrations of 10μg/μL,10μg/μL and 0.1μg/μL,respectively.