Identification of semiochemicals in bumblebees and their social parasites

该项目的一个主要目标是识别在调节大黄蜂寄主及其社会寄生虫繁殖方面具有作用的信号化学物质。在一种比较的方法中，我们将包括一种高度宿主特异性的寄生虫和一种使用不同宿主物种的寄生虫。我们将进行气相色谱-触角检测(GC-EAD)，并测量宿主和寄生虫气味样本的嗅觉诱导的心脏反应，以检测可能作为信号化学物质发挥主要作用的化合物。随后，将GC-EAD活性化合物通过气相色谱-质谱联用(GC-MS)的化学分析进行鉴定和合成。最后，将对接触了GC-EAD活性化合物的各种合成混合物的幼虫寄主工作人员进行生物检测，以确定寄主女王或寄生虫雌性的优势信号。我们将比较两个被调查的寄主-寄生虫系统的寄主和寄生虫的机制，分别是在宿主和寄生虫系统中调节工蜂繁殖的信号化学物质。在该项目的第二部分中，我们将识别寄主巢所涉及的化学信号-识别寄主特有和非寄主特有的Psihyur物种。我们将进行Y管测试，比较不同寄主和非寄主物种的巢标记信号对寄生虫雌性的吸引力，并进行电生理和化学分析(GC-MS)以鉴定活性化合物。最后，我们将测试寄主群体上的印记是否在寄主巢寻找寄生虫雌性的过程中发挥作用。一种比较的方法可能会打开检测和追踪大黄蜂宿主和杜鹃大黄蜂之间化学交流的基本机制的机会。

A primary aim of the project is the identification of semiochemicals with a function in the regulation of reproduction in bumblebee hosts and their social parasites. In a comparative approach, we will include a highly host specific parasite and a parasite that uses different host species. We will perform gas chromatography with antennographic detection (GC-EAD) and measure olfactory induced cardiac responses of odour samples of hosts and parasites to detect compounds that may play a major role as semiochemicals. Subsequently, GC-EAD active compounds will be identified by chemical analyses using the combination of gas chromatography and mass spectrometry (GC-MS) and synthesized. Finally, bioassays with callow host workers that are exposed to various synthetic mixtures of GC-EAD active compounds will be performed in order to identify dominance signals of the host queens or parasite females. We will compare the mechanisms, respectively semiochemicals that act in regulation of worker reproduction in both, hosts and parasites of the two investigated host-parasite systems. In a second part of the project we will identify chemical signals involved in host nest-recognition of the host specific and non host-specific Psithyurs species. We will perform Y-tube tests to compare the attractiveness of nest marking signals of various host- and non-host species to parasite females and electrophysiological and chemical analyses (GC-MS) to identify the active compounds. Finally we will test whether imprinting on host colonies plays a role in host nest searching parasite females. A comparative approach may open the chance to detect and trace basic mechanisms of chemical communication involved in bumblebee hosts and cuckoo bumblebees.