柑橘凤蝶成虫虫体挥发物成分及触角电位反应研究

Analysis of volatile components and electroantennogram responses of adult Papilio xuthus

【目的】蝴蝶虫体的气味是识别同类和异性的重要信息来源。本研究通过分析柑橘凤蝶Papilio xuthus雌雄蝶羽化后挥发物的变化规律,并比较了未交配雌雄蝶对挥发物的触角电位(EAG)反应,为下一步探讨柑橘凤蝶求偶时嗅觉的利用提供依据。【方法】使用顶空固相微萃取(HS-SPME)提取柑橘凤蝶挥发物,并通过气质联用仪(GC-MS)分析SPME提取物中的主要成分,采用触角电位仪(EAG)测定柑橘凤蝶Papilio xuthus对挥发物的触角电位反应。【结果】雌雄蝶羽化后共检测到14类挥发物,主要包括醇类和酯类,其中酯类、萜类在羽化后均有出现。交配时雌雄蝶均共有且含量较高的挥发物有2种(2-乙基己醇、2-乙基己基乙酸酯),交配时雄蝶特有挥发物仅1种(α-法呢烯),未检测到雌蝶特有的挥发物。柑橘凤蝶雌雄蝶从交配前到交配后,其体内的2-乙基己醇、2-乙基己基乙酸酯和α-法呢烯的含量都变化明显。在交配前及交配时2-乙基己醇和α-法呢烯含量增加,而2-乙基己基乙酸酯的含量减少,表明在交配时,可能有大量的2-乙基己醇、2-乙基己基乙酸酯和α-法呢烯释放到体外。并且未交配雌雄蝶对2-乙基己醇、2-乙基己基乙酸酯和α-法呢烯EAG反应均明显高于对照。【结论】根据雌雄蝶羽化后挥发物变化规律及触角电位试验初步检验,推测2-乙基己醇、2-乙基己基乙酸酯在柑橘凤蝶同种识别及同性识别中起作用,特有的挥发物α-法呢烯在柑橘凤蝶同种异性的识别中起作用。

[Objectives]The body scent of butterflies acts as an information carrier facilitating both conspecific recognition and mate recognition.We analyzed volatile compounds from adult male and female Papilio xuthus during different life stages,and used the EAG responses of unmated male and female butterflies to detect volatile compounds.The reactions and behavioral responses of insects to volatile compounds were also compared.[Methods]Volatiles from P.xuthus were collected by the headspace SPME method and identified using GC-MS.Antennal responses to volatile compounds was measured with an electroantennogram(EAG).[Results]In total,14 kinds of volatile compounds were detected during adult eclosion,including alcohols and esters.Among these,esters and terpenes persisted after eclosion.Two kinds of volatile compounds,2-ethyl-1-hexanol and 2-ethylhexyl acetate,were emitted by both males and females during mating.Only one volatile compound(α-farnesene)was unique to males and was only detected during mating.None of the unique volatile compounds identified was found in females.Levels of 2-ethyl-1-hexanol,2-ethylhexyl acetate,and farnesene in both sexes of P.xuthus were significantly different before,and after,mating.Levels of 2-ethyl-1-hexanol and farnesene increased before,and during,mating,whereas the level of 2-ethylhexyl acetate decreased,suggesting that large quantities of 2-ethyl-1-hexanol,2-ethylhexyl acetate,and farnesene are be released by females during mating.The EAG reactions of unmated butterflies to 2-ethyl-1-hexanol,2-ethylhexyl acetate,and farnesene were significantly stronger than those of the control group.[Conclusion]2-ethyl-1-hexanol and 2-ethylhexyl acetate probably play a role in identifying conspecifics of the same sex in P.xuthus,whereas the unique volatile compoundα-farnesene may play a role in identifying the opposite sex.