Behavioral Physiology and Sociobiology (Zoology II), Biocenter, University of Würzburg, Würzburg, Germany.
Imaging Core Facility, Biocenter, University of Würzburg, Würzburg, Germany.
J Comp Neurol. 2021 Jun;529(8):2138-2155. doi: 10.1002/cne.25077. Epub 2020 Dec 10.
The Johnston's organ (JO) in the insect antenna is a multisensory organ involved in several navigational tasks including wind-compass orientation, flight control, graviception, and, possibly, magnetoreception. Here we investigate the three dimensional anatomy of the JO and its neuronal projections into the brain of the desert ant Cataglyphis, a marvelous long-distance navigator. The JO of C. nodus workers consists of 40 scolopidia comprising three sensory neurons each. The numbers of scolopidia slightly vary between different sexes (female/male) and castes (worker/queen). Individual scolopidia attach to the intersegmental membrane between pedicel and flagellum of the antenna and line up in a ring-like organization. Three JO nerves project along the two antennal nerve branches into the brain. Anterograde double staining of the antennal afferents revealed that JO receptor neurons project to several distinct neuropils in the central brain. The T5 tract projects into the antennal mechanosensory and motor center (AMMC), while the T6 tract bypasses the AMMC via the saddle and forms collaterals terminating in the posterior slope (PS) (T6I), the ventral complex (T6II), and the ventrolateral protocerebrum (T6III). Double labeling of JO and ocellar afferents revealed that input from the JO and visual information from the ocelli converge in tight apposition in the PS. The general JO anatomy and its central projection patterns resemble situations in honeybees and Drosophila. The multisensory nature of the JO together with its projections to multisensory neuropils in the ant brain likely serves synchronization and calibration of different sensory modalities during the ontogeny of navigation in Cataglyphis.
昆虫触角中的 Johnston's 器官（JO）是一个多感觉器官，参与了几种导航任务，包括风向罗盘定位、飞行控制、重觉和可能的磁觉。在这里，我们研究了沙漠蚂蚁 Cataglyphis 的 JO 的三维解剖结构及其神经元向大脑的投射，Cataglyphis 是一种出色的远距离导航者。C. nodus 工蚁的 JO 由 40 个感器组成，每个感器包含三个感觉神经元。感器的数量在不同性别（雌性/雄性）和蜂群（工蚁/女王）之间略有不同。单个感器附着在触角的基节和鞭节之间的节间膜上，并排成环状组织。三条 JO 神经沿着两条触角神经分支投射到大脑中。触角传入神经的顺行双重染色显示，JO 受体神经元投射到中央脑中的几个不同神经丛。T5 束投射到触角机械感觉和运动中心（AMMC），而 T6 束通过鞍部绕过 AMMC，并形成分支终止于后坡（PS）（T6I）、腹侧复合体（T6II）和腹外侧原脑（T6III）。JO 和眼窝传入神经的双重标记显示，JO 的输入和来自眼窝的视觉信息在 PS 中紧密贴合。JO 的一般解剖结构及其向蚂蚁大脑中多感觉神经丛的投射模式类似于蜜蜂和果蝇的情况。JO 的多感觉性质及其向蚂蚁大脑中多感觉神经丛的投射可能有助于 Cataglyphis 导航发育过程中不同感觉模态的同步和校准。
