Development and function of perfume signals in orchid bees

化学信号用于许多节肢动物的交配行为，特别是昆虫，在化学复杂性和物质类别上表现出很大的变异性。可能的功能范围从调节配偶/物种识别(识别功能)到雄-雄相互作用中的信号状态和竞争强度(武器功能)，再到向选择性配偶发送遗传适合性信号(装饰功能)。所有三个功能都可以是相同特性的非排他性共同选项，因为它在不同的上下文中显示并且对不同的接收者显示。在本项目中，我们将在一种神秘的化学信号特征--环境衍生的新热带兰花雄性蜜蜂(Euglossini)的‘香水’中评估这些功能。我们将使用新开发的技术进行野外和笼子实验的结合，以(1)监测个体男性香水的发育，(2)测试香水对性展示和交配行为的影响。关于(2)，我们将从我们最近成功地使完全的兰花蜜蜂在飞行笼子中繁殖行为进行推断。作为该项目的中心部分，我们将为处女雌性呈现我们操纵过的香水负荷的雄性的双重选择：有和没有香水(香水持有实验)，香水的数量(香水强度实验)，香水的种类正确性(专一性实验)，以及是否存在可能调节香水专一性的某种主要化合物(HNDB实验)。这些实验的结果，加上对男性与男性相互作用的香水依赖性的分析，将使我们能够评估识别、武器和装饰功能在塑造优生香水进化过程中的重要性，并将有助于我们进一步建立兰花蜜蜂作为研究交配行为、性别选择和物种形成的模式系统。

Chemical signals are used in the mating behavior of many arthropods, especially insects, exhibiting a large variability in chemical complexityand substance classes. Possible functions range from mediating mate/species recognition (recognition function) to signaling status and competitive strength in male-male interactions (armament function) to signaling genetic fitness to choosy mates (ornament function). All three functions may be non-exclusive co-options of the same trait as it is displayed in different contexts and to different receivers. In the present project we will evaluate these functions in an enigmatic chemical signaling trait, the environment-derived ‘perfume’ of male neotropical orchid bees (Euglossini). We will carry out a combination of field and cage experiments using newly developed techniques for (1) monitoring individual male perfume development and (2) for testing perfume effects on sexual display and mating behavior. With regard to (2) we will extrapolate from our recent success in enabling the complete orchid bee (Euglossa dilemma) reproductive behavior in flight cages. As a central part of the project, we will present virgin females with dual choices of males whose perfume loads we have manipulated: with and without perfume (perfume possession experiment), the amount of perfume (perfume intensity experiment), the species-correctness of the perfume (specificity experiment), and the presence of a certain major compound that is likely to mediate perfume specificity (HNDB experiment). The results of these experiments, plus the analysis of perfume-dependence of male-male interactions, will allow us to evaluate the importance of recognition, armament, and ornament functions in shaping the evolution of euglossine perfumes, and will help us to further establish orchid bees as a model system for the study of mating behavior, sexual selection, and speciation.