Kümmerlen Katja, Schlüter Rabea, Harzsch Steffen
Zoological Institute and Museum, University of Greifswald, Greifswald, Mecklenburg-Vorpommern, Germany.
Imaging Center of the Department of Biology, University of Greifswald, Greifswald, Mecklenburg-Vorpommern, Germany.
Open Biol. 2025 Jan;15(5):240397. doi: 10.1098/rsob.240397. Epub 2025 May 7.
Our current understanding of the functional morphology of olfactory systems in arthropods largely relies on information obtained in hexapods. Existing analyses of the olfactory pathway in crustacean representatives have suggested that these animals share several corresponding anatomical elements with hexapod olfactory systems but that the latter likely feature a different olfactory wiring logic from receptor to olfactory glomerulus. This study sets out to further explore the diversity of arthropod olfactory systems by presenting a detailed morphological analysis of the peripheral and central olfactory pathways in an emerging model system, the peracarid crustacean (Malacostraca). These animals feature all neuronal elements that characterize malacostracan crustacean's olfactory systems, and the simplicity of this animal's olfactory system provided the unique opportunity to quantify the numbers of olfactory sensilla and associated sensory neurons, olfactory interneurons and olfactory glomeruli. These data showed that the number of those neuronal elements is highly variable across individuals, contrasting with more stable numbers of neuronal elements in hexapod olfactory systems that typically are characterized by olfactory glomeruli with individual identities and constant numbers. We discuss the possible steps needed for an evolutionary transformation of a malacostracan crustacean type of olfactory system into a hexapod type.
我们目前对节肢动物嗅觉系统功能形态的理解很大程度上依赖于从六足动物获得的信息。对甲壳类动物代表嗅觉通路的现有分析表明，这些动物与六足动物嗅觉系统有几个相应的解剖学元素，但后者从受体到嗅觉小球可能具有不同的嗅觉布线逻辑。本研究旨在通过对一个新兴模型系统——囊虾总目甲壳类动物（软甲纲）的外周和中枢嗅觉通路进行详细的形态学分析，进一步探索节肢动物嗅觉系统的多样性。这些动物具有表征软甲纲甲壳类动物嗅觉系统的所有神经元成分，并且这种动物嗅觉系统的简单性提供了一个独特的机会来量化嗅觉感受器和相关感觉神经元、嗅觉中间神经元以及嗅觉小球的数量。这些数据表明，这些神经元成分的数量在个体间高度可变，这与六足动物嗅觉系统中神经元成分数量更稳定形成对比，六足动物嗅觉系统通常以具有个体特征和恒定数量的嗅觉小球为特征。我们讨论了将软甲纲甲壳类动物类型的嗅觉系统进化转变为六足动物类型所需的可能步骤。
