Excellent Team for Mitigation, Faculty of Forestry and Wood Sciences, Czech University of Life Sciences Prague, Prague, Czech Republic.
Faculty of Science, Charles University, Prague, Czech Republic.
Microsc Res Tech. 2023 Dec;86(12):1610-1625. doi: 10.1002/jemt.24397. Epub 2023 Aug 12.
The double-spined spruce bark beetle, Ips duplicatus, has become an infamous secondary pest of Norway spruce, causing extensive ecological and economic destruction in many Central European countries. Antennae are the primary olfactory organs that play a fundamental role in insect-host chemical communication; therefore, understanding morphology is crucial before conducting electrophysiological investigations. Here, we present our analysis of sensilla types on the antennal surface of I. duplicatus for the first time, using high-resolution-scanning electron microscopy. We studied the external morphological characteristics of antennae and the types, numbers, and distribution of the antennal sensilla in males and females. Our results revealed the presence of five different types of morphologically distinct sensilla: sensilla chaetica, sensilla basiconica, sensilla trichodea, sensilla coeloconica, and Böhm's sensilla. We observed two subtypes of sensilla chaetica (SChI and SChII), four subtypes of sensilla basiconica (SBI, SBII, SBIII, and SBIV), three subtypes of sensilla trichodea (STrII, STrIII, and STrIV) and two subtypes of sensilla coeloconica (SCoI and SCoII), respectively in I. duplicatus males and females. Minor differences in length and numbers between the sexes for some sensilla types were found. Distribution maps for different sensillar types were constructed, and specific areas for the respective sensilla were found. Possible functions of observed sensilla types are discussed. The present study provides a basis for future electrophysiological studies to understand how I. duplicatus detects ecologically important olfactory cues. RESEARCH HIGHLIGHTS: • The first report of morphology and distribution pattern of the antennal sensilla in Ips duplicatus is discussed. • A total of 6 main types and 11 antennal sensilla subtypes were observed in male and female Ips duplicatus. • Minor sex-specific differences were seen in the length and numbers in several sensilla types.
双棘松梢小蠹，Ips duplicatus，已成为挪威云杉的一种臭名昭著的次要害虫，在许多中欧国家造成了广泛的生态和经济破坏。触角是昆虫与宿主化学通讯的主要嗅觉器官；因此，在进行电生理研究之前，了解形态学至关重要。在这里，我们首次使用高分辨率扫描电子显微镜对双棘松梢小蠹触角表面的感觉器类型进行了分析。我们研究了触角的外部形态特征以及雌雄两性触角感觉器的类型、数量和分布。我们的研究结果揭示了存在五种不同形态的感觉器：刚毛感器、锥形感器、毛形感器、腔锥形感器和 Böhm 感觉器。我们观察到两种亚型的刚毛感器（SChI 和 SChII）、四种亚型的锥形感器（SBI、SBII、SBIII 和 SBIV）、三种亚型的毛形感器（STrII、STrIII 和 STrIV）和两种亚型的腔锥形感器（SCoI 和 SCoII），分别在双棘松梢小蠹的雌雄两性中。发现一些感觉器类型在两性之间的长度和数量上存在微小差异。为不同感觉器类型绘制了分布图，并找到了各自感觉器的特定区域。讨论了观察到的感觉器类型的可能功能。本研究为进一步的电生理研究提供了基础，以了解双棘松梢小蠹如何检测生态重要的嗅觉线索。研究亮点：• 讨论了双棘松梢小蠹触角感觉器形态和分布模式的首次报告。• 在雄性和雌性双棘松梢小蠹中观察到总共 6 种主要类型和 11 种触角感觉器亚型。• 几种感觉器类型的长度和数量存在轻微的性别特异性差异。
