ABSTRACT Lepidopteran larvae possess two pairs of styloconic sensilla located on the maxillary galea. These sensilla, namely, the lateral and medial styloconic sensilla, are each composed of a smaller cone, which is inserted into a style. They are thought to play an important role in host plant selection and are the main organs involved in feeding. Ultrastructural examination of these sensilla of fifth instar Lymantria dispar (L.) larvae reveal that they are each ≈70 µm in length and 30 µm in width. Each sensillum consists of a single sensory peg inserted into the socket of a large style. Each peg bears a slightly subapical terminal pore averaging 317 nm in lateral sensilla and 179 nm in medial sensilla. Each sensillum houses five bipolar neurons. The proximal dendritic segment of each neuron gives rise to an unbranched distal dendritic segment. Four of these dendrites terminate near the tip of the sensillum below the pore and bear ultrastructural features consistent with contact chemosensilla. The fifth distal dendrite terminates near the base of the peg and bears ultrastructural features consistent with mechanosensilla. Thus, these sensilla each bear a bimodal chemo-mechanosensory function. The distal dendrites lie within the dendritic channel and are enclosed by a dendritic sheath. The intermediate and outer sheath cells enclose a large sensillar sinus, whereas the smaller ciliary sinus is enclosed by the inner sheath cell. The neurons are ensheathed successively by the inner, intermediate, and outer sheath cells.

中文翻译：

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幼虫 Lymantria dispar (Lepidoptera: Lymantriidae) Galeal Styloconic Sensilla 的精细结构

摘要 鳞翅目幼虫具有两对位于上颌帽状腱膜上的柱状感受器。这些感受器，即外侧和内侧花柱状感受器，每个都由一个较小的锥体组成，锥体插入到一个花柱中。它们被认为在宿主植物选择中起着重要作用，并且是参与摄食的主要器官。对这些五龄 Lymantria dispar (L.) 幼虫的感受器进行超微结构检查，发现它们的长度约为 70 µm，宽度约为 30 µm。每个感器由一个插入大型插座的单一感觉栓组成。每个钉带有一个稍微近尖的末端孔，在外侧感受器中平均为 317 nm，在内侧感受器中为 179 nm。每个感器都有五个双极神经元。每个神经元的近端树突节产生一个无分支的远端树突节。其中四个树突终止于孔隙下方的感受器尖端附近，并具有与接触化学感受器一致的超微结构特征。第五个远端树突终止于桩基部附近，具有与机械感受器一致的超微结构特征。因此，这些感受器各自具有双峰化学机械感应功能。远端树突位于树突通道内并被树突鞘包围。中间和外鞘细胞包围着一个大的感觉窦，而较小的睫状窦被内鞘细胞包围。神经元依次被内鞘细胞、中间鞘细胞和外鞘细胞包裹。第五个远端树突终止于桩基部附近，具有与机械感受器一致的超微结构特征。因此，这些感受器各自具有双峰化学机械感应功能。远端树突位于树突通道内并被树突鞘包围。中间和外鞘细胞包围着一个大的感觉窦，而较小的睫状窦被内鞘细胞包围。神经元依次被内鞘细胞、中间鞘细胞和外鞘细胞包裹。第五个远端树突终止于桩基部附近，具有与机械感受器一致的超微结构特征。因此，这些感受器各自具有双峰化学机械感应功能。远端树突位于树突通道内并被树突鞘包围。中间和外鞘细胞包围着一个大的感觉窦，而较小的睫状窦被内鞘细胞包围。神经元依次被内鞘细胞、中间鞘细胞和外鞘细胞包裹。中间和外鞘细胞包围着一个大的感觉窦，而较小的睫状窦被内鞘细胞包围。神经元依次被内鞘细胞、中间鞘细胞和外鞘细胞包裹。中间和外鞘细胞包围着一个大的感觉窦，而较小的睫状窦被内鞘细胞包围。神经元依次被内鞘细胞、中间鞘细胞和外鞘细胞包裹。