The Evolution of Pheromone Communication in the Genus Leptopilina (Hymenoptera: Figitidae), a Parasitoid of Drosophila.

信息素的起源和进化是化学生态学研究的重要课题之一。近年来，在DFG的资助下，我有机会研究寄生蜂Leptopilina heterotoma（Hyattera，Figitidae）的化学生态学，它是果蝇的一种幼虫寄生蜂。该物种提供了一个罕见的情况下，三倍的信息素简约和昆虫信息素进化的一个非通信化合物的主要例子。我们可以证明L.异瘤菌产生（-）-虹彩霉素（和少量其它环烯醚萜类化合物）并将其用作对抗捕食者的防御性异源激素。此外，L.异源蜂使用（-）-虹彩霉素作为化学线索，以避开已被异源和异源雌虫利用寄主斑块。最后，雌性使用（-）-虹彩霉素作为其雌性性信息素的主要成分。（-）-iridomyrmecin因此最有可能最初演变为防御目的，后来才成为一种信息素。这个项目继续并扩展了我目前DFG项目中所做的研究。在该项目的第一部分，我将使用比较的方法来确定使用环烯醚萜作为防御性的异源激素，化学线索，以避免女性之间的竞争，和性信息素在几种Leptopilina和外群物种。我将联合收割机结合这些数据与分子生物学来阐明这些物种的化学生态学进化。在本课题的第二部分中，我将研究虹彩霉素的立体特异性检测。虹膜霉素分子中有4个手性碳原子，因此存在16种立体异构体。我的行为实验表明，L。异源瘤可以区分（-）-虹彩霉素和（+）-虹彩霉素。利用单感器记录技术，对黑腹叶蝉触角上的感器进行了鉴定。对（-）-iridomyrmecin敏感的heterotoma，并系统地映射雄性和雌性触角上的嗅觉感受器。此外，我将分析雄性触角的转录组以确定推定的OR。除了接收者的对映体特异性检测之外，（-）-虹膜霉素必须由发送者生物合成。在本课题的第三部分，我将从阐明L.异型瘤我将用标记的前体来证实L.异口线虫遵循与在其他昆虫中发现的相同的主要途径。第二步是对L.我相信这个项目的结果将大大有助于我们对昆虫化学通讯进化的理解。

The origin and evolution of pheromones is one of the major questions in chemical ecology. In recent years funding by the DFG gave me the opportunity to study the chemical ecology of the parasitoid wasp Leptopilina heterotoma (Hymenoptera, Figitidae), a larval parasitoid of Drosophila. The species provides a rare case of threefold semiochemical parsimony and prime example of insect pheromone evolution from a non-communicative compound. We could show that females of L. heterotoma produce (-)-iridomyrmecin (and minor amounts of some other iridoid compounds) and use it as a defensive allomone against predators. Furthermore, females of L. heterotoma use (-)-iridomyrmecin as a chemical cue to avoid host patches already exploited by con- and heterospecific females. And finally, the females use (-)-iridomyrmecin as the major component of their female sex pheromone. (-)-iridomyrmecin thus most probably originally evolved for defensive purposes and only became a pheromone later on. This project continues and expands the studies done in my current DFG project. In the first part of the project I will use a comparative approach to identify the use of iridoids as defensive allomones, chemical cue to avoid competition among females, and sex pheromone in several species of Leptopilina and outgroup species. I will combine these data with a molecular phylogeny to shed light on the evolution of the chemical ecology of these species. In the second part of the project I will investigate the stereospecific detection of iridomyrmecin. The molecule of iridomyrmecin has four chiral carbon atoms and thus 16 stereoisomers of iridomyrmecin exist. My behavioral experiments have demonstrated, that males of L. heterotoma can discriminate between (-)-iridomyrmecin and (+)-iridomyrmecin. Using single sensillum recordings, I aim to identify the sensilla on the antennae of L. heterotoma sensitive to (-)-iridomyrmecin and to systematically map the olfactory sensilla on the antenna of males and females. Additionally I will analyze the transcriptome of the antennae of males to identify putative ORs.In addition the enantiospecific detection by the receiver, (-)-iridomyrmecin has to be biosynthezised enantiospecifically by the sender. In the third part of the project I will start to elucidate the biosynthesis pathway of (-)-iridomyrmecin in L. heterotoma. I will use labelled precursors to confirm that iridoid synthesis in L. heterotoma follows the same principal pathway as found in other insects. In the second step I will search the transcriptome of the mandibular gland of L. heterotoma for candidate iridoid synthases.I am convinced that the results from this project will significantly contribute to our understanding of the evolution of chemical communication in insects.