荷兰瓦赫宁根大学的研究表明一只寄生蜂能够学习识别一种由交配过的（或受精的）大菜粉蝶（Pieris brassicae）分泌的气味。这一现象发生在它们从其寄居的菜粉蝶身上爬去一株这只蝴蝶刚产完卵的宿主植物的期间，一天后，这只寄生蜂就能按相同线路飞行。没有此类经历的寄生蜂就不能将交配过的蝴蝶和未受精的蝴蝶区分开。研究员用实验证明长期记忆的产生就是用于记住这种气味。
在交配过程中，雄性大菜粉蝶将一种叫做氰化苯的特别气味传输到其配偶体内。这种气味能阻击雄性情敌。只需一分钟（仅仅0.5分的时间）甘蓝夜蛾赤眼寄居蜂就能利用菜粉蝶的性攻击气味，它们拥有这与生俱来的本领。没有经验的寄生蜂发现并利用性攻击气味来识别交配过的菜粉蝶，然后寄居在它们身上。当这些蝴蝶将它们的卵产在白菜上时，寄居蜂从菜粉蝶身上爬下来将它自己的卵产在蝴蝶刚产下的卵中。通过这种方式，寄居蜂寄居并杀死蝴蝶的后代。
对甘蓝夜蛾赤眼寄居蜂来说，这是一种本能的、固有的行为。但对于与其有近亲关系的广赤眼蜂来说，就不那么适用了。这种蜂寄居于多种蛾子和的蝴蝶，其中包括大菜粉蝶。没有经验的广赤眼蜂像甘蓝夜蛾赤眼寄居蜂一样爬到菜粉蝶身上，但没有对交配过的雌蝶表现出偏好。研究员因此得出结论说广赤眼蜂对氰化苯没有本能反应。
由荷兰瓦赫宁根大学昆虫学实验室的Ties Huigens博士领导的研究小组对这种寄居蜂能否习得这种行为感到好奇。而情况恰好如此：如果广赤眼蜂先前与交配过的蝴蝶有过寄居经历，它就能对这种性攻击气味做出反应。一旦搭过这类蝴蝶的“顺风车”并将卵寄生于蝴蝶卵中之后，它们就会准确地爬到交配过的蝴蝶身上并寄居。仅仅只是“搭便车”或仅寄居于蝴蝶的卵中对它们来说并不足以发展长期记忆力。研究员总结说这种寄生蜂能学着将雌性蝴蝶的性攻击气味和将卵寄生于蝴蝶卵中的好处联系在一起。
寄居蜂甚至在一天后就会继续展示这种才学到的行为，这是长期记忆的一个迹象。为了演示它，研究员提供抑制剂。服用抑制剂（蛋白质合成的抑制剂）的寄居蜂在其搭蝴蝶的“便车”并将其卵寄居于蝴蝶卵中仅一天后，他们就不能对这种性攻击气味做出反应。显然它们不能合成产生长期记忆所需的这种蛋白质。研究表明这些仅有如此小的“大脑”（估计容量比10纳升（nanoliters）还小）的昆虫能形成长期记忆，尽管这种记忆形成需要大量的能量。科学家认为，昆虫在形成长期记忆后更难以抵制类如干燥等的应激状态。
拥有长期记忆对这些生命短暂的寄居蜂来说非常重要，因为一生中只有几次机会搭交配过的蝴蝶的“便车”。如果它们很快就忘记一段有用的经历，就有可能错过这些仅有的机会。来自瓦赫宁根的昆虫学家预计这种策略是一种普遍的现象。因为对于多种谋杀其他昆虫卵的寄居蜂来说，这是很实用的。（生物谷Bioon.com）
生物谷推荐原始出处：
PNAS Published online before print January 12, 2009, doi: 10.1073/pnas.0812277106
Hitch-hiking parasitic wasp learns to exploit butterfly antiaphrodisiac
Martinus E. Huigensa,1, Foteini G. Pashalidoua, Ming-Hui Qianb, Tibor Bukovinszkya, Hans M. Smida, Joop J. A. van Loona, Marcel Dickea and Nina E. Fatourosa
aLaboratory of Entomology, Department of Plant Sciences, Wageningen University, P.O. Box 8031, 6700 EH Wageningen, The Netherlands; and
bDepartment of Forest Protection, Guangdong Academy of Forestry, No. 233 Guangshan 1 Road, Longdong, Tianhe, Guangzhou, Guangdong, 510520, People's Republic of China
Communicated by Thomas Eisner, Cornell University, Ithaca, NY, December 4, 2008 (received for review November 10, 2008)
Abstract
Many insects possess a sexual communication system that is vulnerable to chemical espionage by parasitic wasps. We recently discovered that a hitch-hiking (H) egg parasitoid exploits the antiaphrodisiac pheromone benzyl cyanide (BC) of the Large Cabbage White butterfly Pieris brassicae. This pheromone is passed from male butterflies to females during mating to render them less attractive to conspecific males. When the tiny parasitic wasp Trichogramma brassicae detects the antiaphrodisiac, it rides on a mated female butterfly to a host plant and then parasitizes her freshly laid eggs. The present study demonstrates that a closely related generalist wasp, Trichogramma evanescens, exploits BC in a similar way, but only after learning. Interestingly, the wasp learns to associate an H response to the odors of a mated female P. brassicae butterfly with reinforcement by parasitizing freshly laid butterfly eggs. Behavioral assays, before which we specifically inhibited long-term memory (LTM) formation with a translation inhibitor, reveal that the wasp has formed protein synthesis-dependent LTM at 24 h after learning. To our knowledge, the combination of associatively learning to exploit the sexual communication system of a host and the formation of protein synthesis-dependent LTM after a single learning event has not been documented before. We expect it to be widespread in nature, because it is highly adaptive in many species of egg parasitoids. Our finding of the exploitation of an antiaphrodisiac by multiple species of parasitic wasps suggests its use by Pieris butterflies to be under strong selective pressure.
