Multimodal signalling in the courtship of male parasitoid wasps: testing the multiple messages hypothesis

动物之间通过视觉、化学、声学、振动甚至电信号进行交流。然而，动物在发送重要信号时并不局限于一种信号模态，而是经常将不同的信号模态组合成一个多模态信号。但是，为什么动物要在一个信号中投入使用两种模式的成本呢？一种假设是模式传递不同的信息（多消息假设）。例如，有可能一种模态传递物种身份，而另一种模态传递关于信号者质量的信息（物种识别假说）。求偶行为在动物王国里很普遍，而且通常对发出信号的一方的交配成功率有很大影响。因此，求爱通常是复杂的，不仅使用一种，而且使用几种方式，这并不奇怪。然而，尽管在过去的几年里，求偶行为已经得到了深入的研究，但多种信息在多模式求偶信号进化中的作用仍然不清楚。本研究拟以Leptopilina属拟寄生蜂为模型系统，研究不同的求偶信号成分是否包含不同的信息片段。雄性Leptopilina展示了一种复杂的求爱方式，包括两种元素：扇动翅膀和触须抚摸。我们的目的是验证雄性求偶的两种信号模式（扇动翅膀=振动和触须抚摸可能传递雄性触须信息素=化学）与物种识别假设相对应的假设，化学模式表明物种身份，振动模式表明雄性的质量。在第一个实验中，我们将测试雄性诱导雌性交配的能力与翅膀扇动的特性以及雄性化学特征的组成之间的相关性。在第二步中，我们将操纵在第一个实验中确定的特征，例如，通过减慢扇动翅膀的频率或修改化学特征，并测量对雄性交配成功的影响。在第三部分，我们将测量在求偶期间使用的两种模式的物种特异性。为此，我们将比较三种Leptopilina及其外类群的翅扇动特征和化学特征。此外，我们还将检验这样一种假设，即黄蜂的化学成分反映了个体的亲缘关系，并被用来避免近亲繁殖。在项目的第四部分，我们想测试，被雌性选择的雄性是否比被拒绝的雄性质量更高，或者这样的配对是否会产生更有活力的后代。我们计划通过分析交配过程中转移的精子数量和后代克服宿主免疫系统的能力来衡量雄性的质量。”

Animals communicate with each other using visual, chemical, acoustical, vibratory and even electrical signals. However, animals are not restricted to one signal modality when sending important signals, but frequently combine different modalities into one multimodal signal. But why should animals invest the costs of using two modalities in one signal? One hypothesis is that the modalities convey different information (multiple messages hypothesis). For example, it is possible that one modality conveys species identity while the other modality conveys information on the signaler’s quality (species recognition hypothesis). Courtships are widespread in the animal kingdom and usually strongly affect the mating success of the signaler. Consequently, it is not surprising that courtships are often complex, utilizing not only one but several modalities. However, even though courtship displays have been intensively studied over the last years, the role of multiple messages in the evolution of multimodal courtship signals is still unclear. Here we propose to use parasitoid wasps of the genus Leptopilina as a model system to study multimodal courtship signals and to test whether the different signaling components contain different pieces of information. Males of Leptopilina show a complex courtship display consisting of two elements: wing fanning and antennal stroking. Our aim is to test the hypothesis that the two signal modalities of the male courtship (wing fanning = vibratory and antennal stroking presumably transfers a male antennal pheromone = chemical) correspond to the species recognition hypothesis with the chemical modality signaling the species identity and the vibratory modality signaling the quality of the male. In a first experiment, we will test for a correlation between the ability of males to elicit matings in females and the properties of the wing fanning as well as the composition of the males’ chemical profile. In a second step we will manipulate the characteristics identified in the first experiment by, for example, slowing down the frequency of the wing fanning or by modifying the chemical profile and measure the effect on the male’s mating success. In the third part we will measure the species specificity of both modalities used during courtship. To this end, we will compare the wing fanning characteristics and the chemical profile of three species of Leptopilina and an outgroup. Furthermore, will test the hypothesis that the chemical profile of the wasps reflects the relatedness of individuals and is used to avoid inbreeding. In part four of the project, we want to test, whether the males chosen by the females are of higher quality than rejected males or whether such pairings result in more viable offspring. We are planning to measure the male’s quality by analyzing the number of sperms transferred during mating and offspring quality by the ability of the offspring to overcome the immune system of the host.