Fire ant venom alkaloids act as key attractants for the parasitic phorid fly, Pseudacteon tricuspis (Diptera: Phoridae)
Fire ant venom alkaloids act as key attractants for the parasitic phorid fly, Pseudacteon tricuspis (Diptera: Phoridae)
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DOI：
10.1007/s00114-009-0598-6
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发表时间：
2009-12-01
影响因子：
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通讯作者：
Fadamiro, Henry Y.
中科院分区：
文献类型：
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作者：
Chen, Li;Sharma, Kavita R.;Fadamiro, Henry Y.
褐飞虱是在美国引进的一种引进火蚁Solenopsis spp.的寄生蜂。尽管拟南蝇利用火蚁报警信息素来定位寄主的假设可能是正确的，但我们在先前的一项研究中证明了其他蚂蚁信号化学物质可能参与了三裂叶蜂对火蚁的反应。这项研究是为了确定腺体来源和调节这种相互作用的信号化学物质的身份。首先，我们测试了三星天牛对红火蚁工蚁体内关键部位和腺体提取液的触角电位反应。结果表明，毒腺/毒囊是诱导三星天牛触角活性较强的化合物的主要来源。通过生物测定指导的分离和行为生物测定相结合的方法进行了后续研究，以验证该寄生蜂对火蚁的吸引是由毒液生物碱介导的假设。这些结果证实了三裂叶蜂对不列颠链霉毒的两个生物碱组分(顺式和反式生物碱组分)的反应。通过气相色谱-触角电色谱联用进一步分析，发现了9种蛇毒生物碱成分，其中包括两种新的2，6-二烷基吡啶类化合物，它们能激发三尖杉毒蛾的触角活动。这是首次证明蚂蚁毒液生物碱作为天敌引诱剂的作用。我们提出了一种涉及报警信息素和毒液生物碱的信号化学介导的三尖杉根结线虫寄主定位机制。讨论了这些发现的生态学意义，包括雄性三星虫对发射蚂蚁毒液生物碱的吸引，可能是为了寻找交配位置。
The phorid fly, Pseudacteon tricuspis Borgmeier, is an introduced parasitoid of imported fire ants, Solenopsis spp., in the USA. Although the assumption that phorid flies use fire ant alarm pheromones for host location is probably true, we demonstrated in a previous study the possible involvement of other ant semiochemicals in the response of P. tricuspis to fire ants. This study was conducted to determine the glandular sources and identity of the semiochemicals mediating this interaction. First, we tested the electroantennogram response of P. tricuspis to extracts of key body parts and glands of workers of the red imported fire ant, S. invicta Buren. The results confirm that the poison (venom) gland/sac is the key source of compounds which elicited strong antennal activity in P. tricuspis. Follow-up studies were conducted by using a combination of bioassay-guided fractionation and behavioral bioassays to test the hypothesis that attraction of this parasitoid to fire ants is mediated by venom alkaloids. The results confirm the response of P. tricuspis to physiologically relevant amounts of the two venom alkaloid fractions (cis and trans alkaloid fractions) of S. invicta. Further analysis by coupled gas chromatography-electroantennogram detection revealed nine venom alkaloid components including two novel 2,6-dialkylpiperideines that elicited significant antennal activity in P. tricuspis. This is the first demonstration of the role of venom alkaloids of ants as attractants for their natural enemies. We propose a semiochemical-mediated host location mechanism for P. tricuspis involving both alarm pheromones and venom alkaloids. The ecological significance of these findings, including the attraction of male P. tricuspis to fire ant venom alkaloids, possibly for mate location, is discussed.