Research Center for Advanced Science and Technology, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8904, Japan.
J Insect Physiol. 2011 Nov;57(11):1518-36. doi: 10.1016/j.jinsphys.2011.08.002. Epub 2011 Aug 16.
Flight behaviors in various insect species are closely correlated with their mechanical and neuronal properties. Compared to locusts and flies which have been intensively studied, moths have "intermediate" properties in terms of the neurogenic muscle activations, power generation by indirect muscles, and two-winged-insect-like flapping behavior. Despite these unique characteristics, little is known about the neuronal mechanisms of flight control in moths. We investigated projections of the wing mechanosensory afferents in the central nervous system (CNS) of the hawkmoth, Agrius convolvuli, because the mechanosensory proprioceptive feedback has an essential role for flight control and would be presumably optimized for insect species. We conducted anterograde staining of nine afferent nerves from the fore- and hindwings. All of these afferents projected into the prothoracic, mesothoracic and metathoracic ganglia (TG1, 2 and 3) and had ascending fibers to the head ganglia. Prominent projection areas in the TG1-3 and suboesophageal ganglion (SOG) were common between the forewing, hindwing and contralateral forewing afferents, suggesting that information from different wings are converged at multiple levels presumably for coordinating wing flapping. On the other hand, differences of projections between the fore- and hindwing afferents were observed especially in projection areas of the tegulae in the TG1 and contralateral projections of the anterior forewing nerve in the TGs and SOG, which would reflect functional differences between corresponding mechanoreceptors on each wing. Afferents comprising groups of the campaniform sensilla at the wing bases had prominent ascending pathways to the SOG, resembling the head-neck motor system for gaze control in flies. Double staining of the wing afferents and flight or neck motoneurons also indicated potential connectivity between them. Our results suggest multiple roles of the wing proprioceptive feedback for flight and provide the anatomical basis for further understanding of neuronal mechanisms of the flight system in moths.
在各种昆虫物种中，飞行行为与它们的机械和神经元特性密切相关。与已经被深入研究的蝗虫和苍蝇相比，飞蛾在神经肌肉激活、间接肌肉发电和双翅类昆虫拍打行为方面具有“中间”特性。尽管具有这些独特的特征，但对于飞蛾的飞行控制的神经元机制知之甚少。我们研究了卷叶蛾 Agrius convolvuli 中央神经系统（CNS）中翅膀机械感觉传入的投射，因为机械感觉本体感受反馈对于飞行控制至关重要，并且可能针对昆虫物种进行了优化。我们对来自前翅和后翅的九条传入神经进行了顺行染色。所有这些传入神经都投射到前胸、中胸和后胸神经节（TG1、2 和 3），并具有向头神经节的上升纤维。前翅、后翅和对侧前翅传入神经在 TG1-3 和食管下神经节（SOG）中具有明显的投射区，这表明来自不同翅膀的信息在多个水平上汇聚，可能是为了协调翅膀拍打。另一方面，前翅和后翅传入神经之间的投射差异在 TG1 中的盾片和 TGs 和 SOG 中前翅神经的对侧投射的投射区中观察到，这反映了每个翅膀上对应机械感受器之间的功能差异。翅膀基部的 campaniform 感觉器组成的传入神经具有明显的上升途径到 SOG，类似于苍蝇头部-颈部运动系统，用于凝视控制。翅膀传入神经和飞行或颈部运动神经元的双重染色也表明它们之间存在潜在的连接。我们的结果表明翅膀本体感受反馈在飞行中具有多种作用，并为进一步理解飞蛾飞行系统的神经元机制提供了解剖学基础。
