Dupuy Fabienne, Rouyar Angéla, Deisig Nina, Bourgeois Thomas, Limousin Denis, Wycke Marie-Anne, Anton Sylvia, Renou Michel
Institut d'Ecologie et des Sciences de l'Environnement de Paris-ECOSENS, Institut National de la Recherche Agronomique-UPMC Versailles, France.
Front Physiol. 2017 Feb 10;8:79. doi: 10.3389/fphys.2017.00079. eCollection 2017.
Recognition of intra-specific olfactory signals within a complex environment of plant-related volatiles is crucial for reproduction in male moths. Sex pheromone information is detected by specific olfactory receptor neurons (Phe-ORNs), highly abundant on the male antenna. The information is then transmitted to the pheromone processing macroglomerular complex (MGC) within the primary olfactory center, the antennal lobe, where it is processed by local interneurons and projection neurons. Ultimately a behavioral response, orientation toward the pheromone source, is elicited. Volatile plant compounds (VPCs) are detected by other functional types of olfactory receptor neurons (ORNs) projecting in another area of the antennal lobe. However, Phe-ORNs also respond to some VPCs. Female-produced sex pheromones are emitted within a rich environment of VPCs, some of which have been shown to interfere with the detection and processing of sex pheromone information. As interference between the different odor sources might depend on the spatial and temporal features of the two types of stimuli, we investigated here behavioral and neuronal responses to a brief sex pheromone blend pulse in a VPC background as compared to a control background in the male noctuid moth . We observed male orientation behavior in a wind tunnel and recorded responses of Phe-ORNs and MGC neurons to a brief sex pheromone pulse within a background of individual VPCs. We also recorded the global input signal to the MGC using calcium imaging with the same stimulation protocol. We found that VPCs eliciting a response in Phe-ORNs and MGC neurons masked responses to the pheromone and decreased the contrast between background odor and the sex pheromone at both levels, whereas α-pinene did not interfere with first order processing. The calcium signal produced in response to a VPC background was tonic, lasting longer than the VPC stimulus duration, and masked entirely the pheromone response. One percent heptanal and linalool, in addition to the masking effect, caused a clear delay in responses of MGC neurons to the sex pheromone. Upwind flight toward the pheromone in a wind tunnel was also delayed but otherwise not altered by different doses of heptanal.
在与植物相关的挥发性物质构成的复杂环境中识别种内嗅觉信号，对雄蛾的繁殖至关重要。性信息素信息由特定的嗅觉受体神经元（Phe-ORNs）检测，这些神经元在雄蛾触角上高度丰富。然后该信息被传递到初级嗅觉中枢触角叶内的信息素处理大glomerular复合体（MGC），在那里由局部中间神经元和投射神经元进行处理。最终引发一种行为反应，即朝向信息素源的定向。挥发性植物化合物（VPCs）由投射到触角叶另一区域的其他功能类型的嗅觉受体神经元（ORNs）检测。然而，Phe-ORNs也对一些VPCs有反应。雌蛾产生的性信息素在丰富的VPCs环境中释放，其中一些已被证明会干扰性信息素信息的检测和处理。由于不同气味源之间的干扰可能取决于两种刺激的空间和时间特征，我们在此研究了雄性夜蛾在VPC背景下与对照背景相比对短暂性信息素混合脉冲的行为和神经元反应。我们在风洞中观察了雄蛾的定向行为，并记录了Phe-ORNs和MGC神经元在单个VPCs背景下对短暂性信息素脉冲的反应。我们还使用相同的刺激方案通过钙成像记录了输入到MGC的全局信号。我们发现，在Phe-ORNs和MGC神经元中引发反应的VPCs掩盖了对信息素的反应，并在两个层面上降低了背景气味和性信息素之间的对比度，而α-蒎烯不干扰一级处理。对VPC背景产生的钙信号是持续性的，持续时间长于VPC刺激持续时间，并完全掩盖了信息素反应。除了掩盖作用外，1%的庚醛和芳樟醇还导致MGC神经元对性信息素的反应明显延迟。在风洞中向上风飞向信息素的行为也被延迟，但不同剂量的庚醛在其他方面没有改变这种行为。
