Wang Yan, Brożek Jolanta, Dai Wu
Key Laboratory of Plant Protection Resources and Pest Integrated Management of the Ministry of Education, College of Plant Protection, Northwest A&F University, Yangling 712100, China.
Faculty of Natural Science, Institute of Biology, Biotechnology and Environmental Protection, University of Silesia in Katowice, Bankowa 9, 40-007 Katowice, Poland.
Insects. 2020 Nov 5;11(11):762. doi: 10.3390/insects11110762.
Mouthpart structures were observed in three species of Asopinae using scanning electron microscopy to investigate their morphological disparity. The examined species attack mainly slow-moving, soft-bodied insects, primarily larval forms of the Lepidoptera, and are the natural enemies of many pests. This is the first detailed description of their external mouthparts. The triangular and elongated labrum and four-segmented tube-like labium are longer in species ( (Linnaeus, 1758) and Scott, 1874 than in Schouteden, 1907. The labrum of and appear to be equipped with olfactory sensilla basiconica Sb3, a special type of sensilla with nanopores. The labium surface in all studied species bears 14 types of sensilla (St1-St4, Sb1-7, Sst, Sca1-2). A new characteristic of sensilla trichodea is represented in sensillum St1; in both species, it is classified as an olfactory sensillum with nanopores. The tripartite apex of the labium consists of two lateral lobes and a central membranous lobe having microtrichial extensions. Each lobe has one sensory field, including sensilla basiconica (Sb7), sensilla styloconica (Sst), and sensilla trichodea (St4). In the three studied predatory stink bugs, each mandibular stylet tip has five irregular teeth and three long, pointed hooks. The two opposing maxillae, which are held together by a tongue-and-groove system, form a food canal and a salivary canal. The apices of the right maxilla have small teeth and few short barbs along the edge of the food canal. In and , there are 5 teeth, while in there are 2. Based on structural differences, we inferred that the hook-shaped mandibular teeth, right maxilla with small teeth, and few short barbs along edge of the food canal are more adapted for a predatory lifestyle. Predatory stink bugs use sharp recurved hooks and irregular teeth penetrating, tearing, or filing devices that aid in the mechanical disruption of host tissue. Stiff bristles in the food canal may indicate their possible adaptation to feeding on insect larvae. The evolution of mouthpart morphology and the putative functional significance of sensilla are discussed, providing insight into the sensory mechanism.
利用扫描电子显微镜观察了三种长蝽亚科昆虫的口器结构，以研究它们的形态差异。所研究的物种主要捕食行动缓慢、身体柔软的昆虫，主要是鳞翅目幼虫，是许多害虫的天敌。这是对它们外部口器的首次详细描述。三角形且细长的上唇和分四节的管状下唇在（林奈，1758年）和（斯科特，1874年）的物种中比在（肖特登，1907年）的物种中更长。和的上唇似乎配备有嗅觉锥形感器Sb3，这是一种具有纳米孔的特殊感器类型。所有研究物种的下唇表面有14种感器（St1 - St4、Sb1 - 7、Sst、Sca1 - 2）。感器St1呈现了毛形感器的一个新特征；在这两个物种中，它被归类为具有纳米孔的嗅觉感器。下唇的三分顶端由两个侧叶和一个具有微毛延伸的中央膜质叶组成。每个叶有一个感觉场，包括锥形感器（Sb7）、柱形感器（Sst）和毛形感器（St4）。在三种研究的捕食性蝽象中，每个下颚口针尖端有五个不规则齿和三个长而尖的钩。由榫槽系统连接在一起的两个相对的上颚形成一个食物道和一个唾液道。右上颚的顶端在食物道边缘有小齿和一些短倒刺。在和中有5个齿，而在中有2个齿。基于结构差异，我们推断钩形下颚齿、带有小齿的右上颚以及食物道边缘的少量短倒刺更适合捕食性生活方式。捕食性蝽象使用尖锐的弯曲钩和不规则齿作为穿透、撕裂或锉磨装置，有助于对宿主组织进行机械破坏。食物道中的硬刚毛可能表明它们可能适应以昆虫幼虫为食。讨论了口器形态的进化以及感器的假定功能意义，为感觉机制提供了见解。
