Tang Qing-Bo, Hong Zhen-Zhen, Cao Huan, Yan Feng-Ming, Zhao Xin-Cheng
Department of Entomology, College of Plant Protection, Henan Agricultural University, Zhengzhou, Henan, China.
Neuroreport. 2015 Aug 19;26(12):703-11. doi: 10.1097/WNR.0000000000000413.
The medial and lateral styloconic sensilla, constituting the main taste organs of lepidopterous caterpillars, were investigated in the oligophagous species, Helicoverpa assulta (Guenée) (Lepidoptera: Noctuidae). In this paper, the two sensilla were morphologically and physiologically characterized by scanning electron microscopy and tip recordings, respectively. The central projections of their respective sensory neurons were mapped by anterograde staining experiments combined with confocal laser scanning microscopy. The results showed that the two sensilla are in general morphologically similar. However, the size of the peg on the medial sensillum is significantly greater than that of the lateral. Tobacco leaf saps, sinigrin, and nicotine elicited strong responses from neurons housed by the medial sensillum, whereas sucrose activated primarily the lateral sensillum. All stained neurons in either sensillum showed a projection pattern involving axons entering the subesophageal ganglion through the ipsilateral maxillary and passing further on through the ipsilateral circumesophageal connective to the tritocerebrum of the brain. In the subesophageal ganglion, the axons targeted two areas: the ventrolateral section and the region near the neuromere midline. One distinction between the staining patterns originating from the two sensilla, however, is that axons arising from the medial sensillum, and not the lateral, give off some additional neural branches in the subesophageal ganglion including a few arborizations surrounding a tract, plus a long process extending posteriorly along the midline. Differences in the central projections derived from the two sensilla styloconica have not been reported previously.
在寡食性昆虫烟青虫（Helicoverpa assulta (Guenée)，鳞翅目：夜蛾科）中，对构成鳞翅目毛虫主要味觉器官的内侧和外侧栓锥感器进行了研究。在本文中，分别通过扫描电子显微镜和尖端记录对这两种感器进行了形态学和生理学特征分析。通过顺行染色实验结合共聚焦激光扫描显微镜对其各自感觉神经元的中枢投射进行了映射。结果表明，这两种感器在形态上总体相似。然而，内侧感器上栓的尺寸明显大于外侧感器。烟叶汁液、黑芥子硫苷和尼古丁能引起内侧感器中神经元的强烈反应，而蔗糖主要激活外侧感器。两种感器中所有染色的神经元都呈现出一种投射模式，即轴突通过同侧上颌进入咽下神经节，然后进一步通过同侧围食管神经连索到达脑的后脑。在咽下神经节中，轴突靶向两个区域：腹外侧部分和神经节中线附近区域。然而，源自这两种感器的染色模式之间的一个区别是，内侧感器而非外侧感器的轴突在咽下神经节中发出一些额外的神经分支，包括围绕一条束的一些分支，以及沿着中线向后延伸的一个长突起。此前尚未报道过源自两种栓锥感器的中枢投射的差异。
