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方面表现出很大的变化。可能的功能范围从调节配偶/物种识别（识别功能）到雄性间相互作用中的地位和竞争强度信号（武装功能），再到选择配偶的遗传适应性信号（装饰功能）。这三个功能可能是同一特性的非排他性共选，因为它在不同的上下文中显示给不同的接收者。在本项目中，我们将在一个神秘的化学信号特征中评估这些功能，即雄性新热带兰花蜂（Euglossini）的环境衍生“香水”。我们将使用新开发的技术进行现场和笼子实验，以(1)监测雄性个体香水的发展，(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兰蜂（Euglossa dilemma）在飞行笼中完全繁殖的行为中推断。作为该项目的核心部分，我们将向处女雌性提供我们操纵的香水负荷的雄性的双重选择：有和没有香水（香水占有实验），香水的数量（香水强度实验），香水的物种正确性（特异性实验），以及可能介导香水特异性的某种主要化合物的存在（HNDB实验）。这些实验的结果，加上对雄性相互作用对香水依赖性的分析，将使我们能够评估识别、武器和装饰功能在塑造丁香香气进化中的重要性，并将帮助我们进一步建立兰花蜂作为交配行为、性选择和物种形成研究的模型系统。

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.